diff --git a/CHANGELOG.md b/CHANGELOG.md
index ca753fa..2f60413 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,30 @@
 ## [Unreleased]
 
+## [0.2.0] - 2024-02-27
+
+### Added
+
+- User entity and your context to handle people business rules.
+- Context for new user registration.
+- Bcrypt to handle password issues.
+- Phonelib to handle phone issues.
+- Logger provider with level configuration.
+- Configure i18n.
+- `pt-BR` translation.
+- `en-US` translation.
+- Add `pub/sub` pattern and API with dry-events.
+- Add `ActiveSupport` to the main application to facilitate general development.
+- Configure database cleaner for suite of tests.
+
+### Fixed
+
+- Adjusting lint with standardrb throughout the code.
+- Lifecyle for core provider.
+
+### Changed
+
+- Adjusting directory patterns for test coverage.
+
 ## [0.1.0] - 2024-02-06
 
 - Initial release
diff --git a/Gemfile b/Gemfile
index ec3061a..ca1daec 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,6 +6,7 @@ source "https://rubygems.org"
 gemspec
 
 gem "activesupport", "7.1.3"
+gem "bcrypt", "3.1.20"
 gem "dotenv", "3.0.2"
 gem "dry-events", "1.0.1"
 gem "dry-matcher", "1.0.0"
@@ -14,6 +15,7 @@ gem "dry-system", "1.0.1"
 gem "dry-validation", "1.10.0"
 gem "money", "6.16.0"
 gem "pg", "1.5.5"
+gem "phonelib", "0.8.7"
 gem "rake", "13.1.0"
 gem "rom", "5.3.0"
 gem "rom-sql", "3.6.2"
diff --git a/Gemfile.lock b/Gemfile.lock
index b55b68b..7bc5b73 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    auction_fun_core (0.1.0)
+    auction_fun_core (0.2.0)
 
 GEM
   remote: https://rubygems.org/
@@ -18,6 +18,7 @@ GEM
       tzinfo (~> 2.0)
     ast (2.4.2)
     base64 (0.2.0)
+    bcrypt (3.1.20)
     bigdecimal (3.1.6)
     coderay (1.1.3)
     concurrent-ruby (1.2.3)
@@ -104,6 +105,7 @@ GEM
       ast (~> 2.4.1)
       racc
     pg (1.5.5)
+    phonelib (0.8.7)
     pry (0.14.2)
       coderay (~> 1.1)
       method_source (~> 1.0)
@@ -209,6 +211,7 @@ PLATFORMS
 DEPENDENCIES
   activesupport (= 7.1.3)
   auction_fun_core!
+  bcrypt (= 3.1.20)
   database_cleaner-sequel (= 2.0.2)
   dotenv (= 3.0.2)
   dry-events (= 1.0.1)
@@ -219,6 +222,7 @@ DEPENDENCIES
   faker (= 3.2.3)
   money (= 6.16.0)
   pg (= 1.5.5)
+  phonelib (= 0.8.7)
   pry (= 0.14.2)
   rake (= 13.1.0)
   rom (= 5.3.0)
diff --git a/config/app.rb b/config/app.rb
index 6886832..4aea664 100644
--- a/config/app.rb
+++ b/config/app.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
-require_relative 'application'
+require_relative "application"
 
 AuctionFunCore::Application.finalize!
diff --git a/config/application.rb b/config/application.rb
index 05cb64a..62e27d2 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -1,30 +1,31 @@
 # frozen_string_literal: true
 
-require_relative 'boot'
+require_relative "boot"
 
-require 'zeitwerk'
-require 'i18n'
-require 'dry/system'
-require 'dry/system/loader/autoloading'
-require 'dry/auto_inject'
-require 'dry/types'
+require "bcrypt"
+require "zeitwerk"
+require "i18n"
+require "dry/system"
+require "dry/system/loader/autoloading"
+require "dry/auto_inject"
+require "dry/types"
 
 module AuctionFunCore
   # Main class (Add doc)
   class Application < Dry::System::Container
     I18n.available_locales = %w[en-US pt-BR]
-    I18n.default_locale = 'pt-BR'
-    use :env, inferrer: -> { ENV.fetch('APP_ENV', 'development').to_sym }
+    I18n.default_locale = "pt-BR"
+    use :env, inferrer: -> { ENV.fetch("APP_ENV", "development").to_sym }
     use :zeitwerk, run_setup: true, eager_load: true
 
     configure do |config|
-      config.root = File.expand_path('..', __dir__)
+      config.root = File.expand_path("..", __dir__)
 
-      config.component_dirs.add 'lib' do |dir|
+      config.component_dirs.add "lib" do |dir|
         dir.auto_register = true
         dir.loader = Dry::System::Loader::Autoloading
         dir.add_to_load_path = true
-        dir.namespaces.add 'auction_fun_core', key: nil
+        dir.namespaces.add "auction_fun_core", key: nil
       end
     end
   end
diff --git a/config/boot.rb b/config/boot.rb
index 5dee28d..2af1743 100644
--- a/config/boot.rb
+++ b/config/boot.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-ENV['APP_ENV'] ||= 'development'
+ENV["APP_ENV"] ||= "development"
 
-require 'bundler'
-Bundler.setup(:default, ENV.fetch('APP_ENV', nil))
+require "bundler"
+Bundler.setup(:default, ENV.fetch("APP_ENV", nil))
 
 unless defined?(Dotenv)
-  require 'dotenv'
+  require "dotenv"
   Dotenv.load(".env.#{ENV.fetch("APP_ENV", nil)}")
-  Dotenv.require_keys('DATABASE_URL')
+  Dotenv.require_keys("DATABASE_URL")
 end
diff --git a/config/locales/contracts/en-US.yml b/config/locales/contracts/en-US.yml
new file mode 100644
index 0000000..c466bbb
--- /dev/null
+++ b/config/locales/contracts/en-US.yml
@@ -0,0 +1,66 @@
+en-US:
+  contracts:
+    errors:
+      or: "or"
+      array?: "must be an array"
+      empty?: "must be empty"
+      excludes?: "must not include %{value}"
+      excluded_from?:
+        arg:
+          default: "must not be one of: %{list}"
+          range: "must not be one of: %{list_left} - %{list_right}"
+      exclusion?: "must not be one of: %{list}"
+      eql?: "must be equal to %{left}"
+      not_eql?: "must not be equal to %{left}"
+      filled?: "must be filled"
+      format?: "is in invalid format"
+      number?: "must be a number"
+      odd?: "must be odd"
+      even?: "must be even"
+      gt?: "must be greater than %{num}"
+      gteq?: "must be greater than or equal to %{num}"
+      hash?: "must be a hash"
+      included_in?:
+        arg:
+          default: "must be one of: %{list}"
+          range: "must be one of: %{list_left} - %{list_right}"
+      inclusion?: "must be one of: %{list}"
+      includes?: "must include %{value}"
+      bool?: "must be boolean"
+      true?: "must be true"
+      false?: "must be false"
+      int?: "must be an integer"
+      float?: "must be a float"
+      decimal?: "must be a decimal"
+      date?: "must be a date"
+      date_time?: "must be a date time"
+      time?: "must be a time"
+      key?: "is required"
+      attr?: "is required"
+      lt?: "must be less than %{num}"
+      lteq?: "must be less than or equal to %{num}"
+      max_size?: "size cannot be greater than %{num}"
+      min_size?: "size cannot be less than %{num}"
+      none?: "cannot be defined"
+      str?: "must be a string"
+      type?: "must be %{type}"
+      size?:
+        arg:
+          default: "size must be %{size}"
+          range: "size must be within %{size_left} - %{size_right}"
+        value:
+          string:
+            arg:
+              default: "length must be %{size}"
+              range: "length must be within %{size_left} - %{size_right}"
+      custom:
+        errors:
+          default:
+            taken: "has already been taken"
+            not_found: "not found"
+            password_confirmation: "doesn't match password"
+          macro:
+            email_format: "need to be a valid email"
+            name_format: "must be between %{min} and %{max} characters"
+            password_format: "must be between %{min} and %{max} characters"
+            phone_format: "need to be a valid mobile number"
diff --git a/config/locales/contracts/pt-BR.yml b/config/locales/contracts/pt-BR.yml
new file mode 100644
index 0000000..1ba8742
--- /dev/null
+++ b/config/locales/contracts/pt-BR.yml
@@ -0,0 +1,65 @@
+pt-BR:
+  contracts:
+    errors:
+      or: "ou"
+      array?: "deve ser um array"
+      empty?: "deve ficar vazio"
+      excludes?: "não deve incluir %{value}"
+      excluded_from?:
+        arg:
+          default: "não deve ser um de: %{list}"
+          range: "não deve ser um de: %{list_left} - %{list_right}"
+      exclusion?: "não deve ser um de: %{list}"
+      eql?: "deve ser igual a %{left}"
+      not_eql?: "não deve ser igual a %{left}"
+      filled?: "deve ser preenchido"
+      format?: "está em formato inválido"
+      number?: "deve ser um número"
+      odd?: "deve ser ímpar"
+      even?: "deve ser par"
+      gt?: "deve ser maior que %{num}"
+      gteq?: "deve ser maior ou igual a %{num}"
+      hash?: "deve ser do tipo hash"
+      included_in?:
+        arg:
+          default: "deve ser um de: %{list}"
+          range: "deve ser um de: %{list_left} - %{list_right}"
+      inclusion?: "deve ser um de: %{list}"
+      includes?: "deve incluir %{value}"
+      bool?: "deve ser booleano"
+      true?: "deve ser verdadeiro"
+      false?: "deve ser falso"
+      int?: "deve ser um número inteiro"
+      float?: "deve ser um número real"
+      decimal?: "deve ser um número decimal"
+      date?: "deve ser no formato de data"
+      date_time?: "deve ser no formato de data e hora"
+      time?: "deve ser no formato de tempo"
+      key?: "é requerido"
+      attr?: "é requerido"
+      lt?: "deve ser menor que %{num}"
+      lteq?: "deve ser menor ou igual a %{num}"
+      max_size?: "tamanho não pode ser maior que %{num}"
+      min_size?: "tamanho não pode ser menor que %{num}"
+      none?: "não pode ser definido"
+      str?: "deve ser do tipo texto"
+      type?: "deve ser do tipo %{type}"
+      size?:
+        arg:
+          default: "tamanho deve ser %{size}"
+          range: "tamanho deve ser entre %{size_left} e %{size_right}"
+        value:
+          string:
+            arg:
+              default: "deve ser %{size} caracteres"
+              range: "deve ser entre %{size_left} e %{size_right} caracteres"
+      custom:
+        default:
+          taken: "não está disponível"
+          not_found: "não encontrado"
+          password_confirmation: "não corresponde à senha"
+        macro:
+          email_format: "não é um email válido"
+          name_format: "deve ter entre %{min} e %{max} caracteres"
+          password_format: "deve ter entre %{min} e %{max} caracteres"
+          phone_format: "não é um número de celular válido"
diff --git a/db/migrate/20240217115734_create_users.rb b/db/migrate/20240217115734_create_users.rb
new file mode 100644
index 0000000..f3541fa
--- /dev/null
+++ b/db/migrate/20240217115734_create_users.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+ROM::SQL.migration do
+  change do
+    create_table(:users) do
+      primary_key :id
+      column :name, String, null: false
+      column :email, String, null: false
+      column :phone, String, null: false
+      column :password_digest, String, null: false
+      column :active, TrueClass, null: false, default: true
+      column :created_at, DateTime, null: false
+      column :updated_at, DateTime, null: false
+
+      index :email, unique: true
+      index :phone, unique: true
+    end
+  end
+end
diff --git a/lib/auction_fun_core.rb b/lib/auction_fun_core.rb
index cc3ddea..2a63167 100644
--- a/lib/auction_fun_core.rb
+++ b/lib/auction_fun_core.rb
@@ -1,17 +1,17 @@
 # frozen_string_literal: true
 
 require_relative "auction_fun_core/version"
-require 'zeitwerk'
+require "zeitwerk"
 
-require_relative '../config/boot'
-require_relative '../config/application'
+require_relative "../config/boot"
+require_relative "../config/application"
 
 module AuctionFunCore
   class Error < StandardError; end
 
   def self.root
-    File.expand_path '..', __dir__
+    File.expand_path "..", __dir__
   end
 
-  autoload :Application, Pathname.new(File.expand_path('../config/application', __dir__))
+  autoload :Application, Pathname.new(File.expand_path("../config/application", __dir__))
 end
diff --git a/lib/auction_fun_core/commands/user_context/create_user.rb b/lib/auction_fun_core/commands/user_context/create_user.rb
new file mode 100644
index 0000000..5b42de9
--- /dev/null
+++ b/lib/auction_fun_core/commands/user_context/create_user.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module AuctionFunCore
+  module Commands
+    module UserContext
+      ##
+      # Abstract base class for insert new tuples on users table.
+      # @abstract
+      class CreateUser < ROM::Commands::Create[:sql]
+        relation :users
+        register_as :create
+        result :one
+
+        use :timestamps
+        timestamp :created_at, :updated_at
+      end
+    end
+  end
+end
diff --git a/lib/auction_fun_core/contracts/application_contract.rb b/lib/auction_fun_core/contracts/application_contract.rb
new file mode 100644
index 0000000..5c8f550
--- /dev/null
+++ b/lib/auction_fun_core/contracts/application_contract.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require "phonelib"
+
+module AuctionFunCore
+  module Contracts
+    # Abstract base class for contracts.
+    # @abstract
+    class ApplicationContract < Dry::Validation::Contract
+      I18N_MACRO_SCOPE = "contracts.errors.custom.macro"
+      EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d-]+(\.[a-z\d-]+)*\.[a-z]+\z/i
+      MIN_NAME_LENGTH = 6
+      MAX_NAME_LENGTH = 128
+      MIN_PASSWORD_LENGTH = 6
+      MAX_PASSWORD_LENGTH = 128
+
+      config.messages.backend = :i18n
+      config.messages.default_locale = I18n.default_locale
+      config.messages.top_namespace = "contracts"
+      config.messages.load_paths << Application.root.join("config/locales/contracts/#{I18n.default_locale}.yml").to_s
+
+      register_macro(:email_format) do
+        next if EMAIL_REGEX.match?(value)
+
+        key.failure(I18n.t(:email_format, scope: I18N_MACRO_SCOPE))
+      end
+
+      register_macro(:name_format) do
+        next if value.length.between?(MIN_NAME_LENGTH, MAX_NAME_LENGTH)
+
+        key.failure(
+          I18n.t(:name_format, scope: I18N_MACRO_SCOPE, min: MIN_NAME_LENGTH, max: MAX_NAME_LENGTH)
+        )
+      end
+
+      register_macro(:phone_format) do
+        next if ::Phonelib.parse(value).valid?
+
+        key.failure(I18n.t(:phone_format, scope: I18N_MACRO_SCOPE))
+      end
+
+      register_macro(:password_format) do
+        next if value.length.between?(MIN_PASSWORD_LENGTH, MAX_PASSWORD_LENGTH)
+
+        key.failure(
+          I18n.t(:password_format, scope: I18N_MACRO_SCOPE, min: MIN_PASSWORD_LENGTH, max: MAX_PASSWORD_LENGTH)
+        )
+      end
+    end
+  end
+end
diff --git a/lib/auction_fun_core/contracts/user_context/registration_contract.rb b/lib/auction_fun_core/contracts/user_context/registration_contract.rb
new file mode 100644
index 0000000..07b3759
--- /dev/null
+++ b/lib/auction_fun_core/contracts/user_context/registration_contract.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+module AuctionFunCore
+  module Contracts
+    module UserContext
+      # Contract class to create new users.
+      class RegistrationContract < ApplicationContract
+        I18N_SCOPE = "contracts.errors.custom.default"
+
+        option :user_repository, default: proc { Repos::UserContext::UserRepository.new }
+
+        # @param [Hash] opts Sets an allowed list of parameters, as well as some initial validations.
+        params do
+          required(:name)
+          required(:email)
+          required(:phone)
+          required(:password)
+          required(:password_confirmation)
+
+          before(:value_coercer) do |result|
+            result.to_h.compact
+          end
+
+          # Normalize and add default values
+          after(:value_coercer) do |result|
+            result.update(email: result[:email].strip.downcase) if result[:email]
+            result.update(phone: result[:phone].tr_s("^0-9", "")) if result[:phone]
+          end
+        end
+
+        rule(:name).validate(:name_format)
+
+        # Validation for email.
+        # It must validate the format and uniqueness in the database.
+        rule(:email).validate(:email_format)
+        rule(:email) do
+          # Email should be unique on database
+          if !rule_error?(:email) && user_repository.exists?(email: value)
+            key.failure(I18n.t(:taken, scope: I18N_SCOPE))
+          end
+        end
+
+        # Validation for phone.
+        # It must validate the format and uniqueness in the database.
+        rule(:phone).validate(:phone_format)
+        rule(:phone) do
+          if !rule_error?(:phone) && user_repository.exists?(phone: value)
+            key.failure(I18n.t(:taken, scope: I18N_SCOPE))
+          end
+        end
+
+        # Validation for password.
+        # Check if the confirmation matches the password.
+        rule(:password).validate(:password_format)
+        rule(:password, :password_confirmation) do
+          if !rule_error?(:password) && values[:password] != values[:password_confirmation]
+            key(:password_confirmation).failure(I18n.t(:password_confirmation, scope: I18N_SCOPE))
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/auction_fun_core/entities/user.rb b/lib/auction_fun_core/entities/user.rb
new file mode 100644
index 0000000..3757d47
--- /dev/null
+++ b/lib/auction_fun_core/entities/user.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module AuctionFunCore
+  module Entities
+    # User Relations class. This return simple objects with attribute readers
+    # to represent data in your user.
+    class User < ROM::Struct
+      def info
+        attributes.except(:password_digest)
+      end
+    end
+  end
+end
diff --git a/lib/auction_fun_core/events/app.rb b/lib/auction_fun_core/events/app.rb
new file mode 100644
index 0000000..903c405
--- /dev/null
+++ b/lib/auction_fun_core/events/app.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module AuctionFunCore
+  module Events
+    # Event class to register business events on system.
+    # @see https://dry-rb.org/gems/dry-events/main/
+    class App
+      # @!parser include Dry::Events::Publisher[:app]
+      include Dry::Events::Publisher[:app]
+
+      register_event("users.registration")
+    end
+  end
+end
diff --git a/lib/auction_fun_core/events/listener.rb b/lib/auction_fun_core/events/listener.rb
new file mode 100644
index 0000000..4b3ecfb
--- /dev/null
+++ b/lib/auction_fun_core/events/listener.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module AuctionFunCore
+  module Events
+    # Event class that can listen business events.
+    # @see https://dry-rb.org/gems/dry-events/main/#event-listeners
+    class Listener
+      # Listener for to *users.registration* event.
+      # @param event [ROM::Struct::User] the user object
+      def on_users_registration(user)
+        logger("New registered user: #{user.to_h}")
+      end
+
+      private
+
+      # Append message to system log.
+      # @param message [String] the message
+      def logger(message)
+        Application[:logger].info(message)
+      end
+    end
+  end
+end
diff --git a/lib/auction_fun_core/operations/base.rb b/lib/auction_fun_core/operations/base.rb
new file mode 100644
index 0000000..4845b2f
--- /dev/null
+++ b/lib/auction_fun_core/operations/base.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module AuctionFunCore
+  module Operations
+    # Abstract base class for operations.
+    # @abstract
+    class Base
+      include Dry::Monads[:do, :maybe, :result, :try]
+    end
+  end
+end
diff --git a/lib/auction_fun_core/operations/user_context/registration_operation.rb b/lib/auction_fun_core/operations/user_context/registration_operation.rb
new file mode 100644
index 0000000..cc83697
--- /dev/null
+++ b/lib/auction_fun_core/operations/user_context/registration_operation.rb
@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+module AuctionFunCore
+  module Operations
+    module UserContext
+      ##
+      # Operation class for create new users.
+      #
+      class RegistrationOperation < AuctionFunCore::Operations::Base
+        include Import["contracts.user_context.registration_contract"]
+        include Import["repos.user_context.user_repository"]
+
+        def self.call(attributes, &block)
+          operation = new.call(attributes)
+
+          return operation unless block
+
+          Dry::Matcher::ResultMatcher.call(operation, &block)
+        end
+
+        # @todo Add custom doc
+        def call(attributes)
+          values = yield validate(attributes)
+          values_with_encrypt_password = yield encrypt_password(values)
+
+          user_repository.transaction do |_t|
+            @user = yield persist(values_with_encrypt_password)
+
+            yield publish_user_registration(@user.id)
+          end
+
+          Success(@user)
+        end
+
+        # Calls the user creation contract class to perform the validation
+        # of the informed attributes.
+        # @param attrs [Hash] user attributes
+        # @return [Dry::Monads::Result::Success, Dry::Monads::Result::Failure]
+        def validate(attrs)
+          registration_contract.call(attrs).to_monad
+        end
+
+        # Transforms the password attribute, encrypting it to be saved in the database.
+        # @param result [Hash] User valid contract attributes
+        # @return [Hash] Valid user database
+        def encrypt_password(attrs)
+          attributes = attrs.to_h.except(:password)
+
+          Success(
+            {**attributes, password_digest: BCrypt::Password.create(attrs[:password])}
+          )
+        end
+
+        # Calls the user repository class to persist the attributes in the database.
+        # @param result [Hash] User validated attributes
+        # @return [ROM::Struct::User]
+        def persist(result)
+          Success(user_repository.create(result))
+        end
+
+        # Triggers the publication of event *users.registration*.
+        # @param user_id [Integer] User ID
+        # @return [Dry::Monads::Result::Success]
+        def publish_user_registration(user_id)
+          user = user_repository.by_id!(user_id)
+
+          Success(
+            Application[:event].publish("users.registration", user.info)
+          )
+        end
+      end
+    end
+  end
+end
diff --git a/lib/auction_fun_core/relations/users.rb b/lib/auction_fun_core/relations/users.rb
new file mode 100644
index 0000000..0426529
--- /dev/null
+++ b/lib/auction_fun_core/relations/users.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module AuctionFunCore
+  module Relations
+    # SQL relation for users.
+    # @see https://rom-rb.org/5.0/learn/sql/relations/
+    class Users < ROM::Relation[:sql]
+      use :pagination, per_page: 10
+
+      schema(:users, infer: true) do
+        attribute :id, Types::Integer
+        attribute :name, Types::String
+        attribute :email, Types::String
+        attribute :phone, Types::String
+        attribute :active, Types::Bool
+
+        primary_key :id
+      end
+
+      struct_namespace Entities
+      auto_struct(true)
+    end
+  end
+end
diff --git a/lib/auction_fun_core/repos/user_context/user_repository.rb b/lib/auction_fun_core/repos/user_context/user_repository.rb
new file mode 100644
index 0000000..98aca69
--- /dev/null
+++ b/lib/auction_fun_core/repos/user_context/user_repository.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+module AuctionFunCore
+  module Repos
+    module UserContext
+      # SQL repository for users.
+      class UserRepository < ROM::Repository[:users]
+        include Import["container"]
+
+        struct_namespace Entities
+        commands :create, update: :by_pk, delete: :by_pk
+
+        # Returns all users in database.
+        # @return [Array<ROM::Struct::User>, []]
+        def all
+          users.to_a
+        end
+
+        # Returns the total number of users in database.
+        # @return [Integer]
+        def count
+          users.count
+        end
+
+        # Mount SQL conditions in query for search in database.
+        # @param conditions [Hash] DSL Dataset
+        # @return [AuctionCore::Relations::Users]
+        def query(conditions)
+          users.where(conditions)
+        end
+
+        # Search user in database by primary key.
+        # @param id [Integer] User ID
+        # @return [ROM::Struct::User, nil]
+        def by_id(id)
+          users.by_pk(id).one
+        end
+
+        # Search user in database by primary key.
+        # @param id [Integer] User ID
+        # @raise [ROM::TupleCountMismatchError] if not found on database
+        # @return [ROM::Struct::Auction]
+        def by_id!(id)
+          users.by_pk(id).one!
+        end
+
+        # Checks if it returns any user given one or more conditions.
+        # @param conditions [Hash] DSL Dataset
+        # @return [true] when some user is returned from the given condition.
+        # @return [false] when no user is returned from the given condition.
+        def exists?(conditions)
+          users.exist?(conditions)
+        end
+      end
+    end
+  end
+end
diff --git a/lib/auction_fun_core/version.rb b/lib/auction_fun_core/version.rb
index e34875d..472ccc3 100644
--- a/lib/auction_fun_core/version.rb
+++ b/lib/auction_fun_core/version.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module AuctionFunCore
-  VERSION = "0.1.0"
+  VERSION = "0.2.0"
 
   # Required class module is a gem dependency
   class Version; end
diff --git a/spec/auction_fun_core/contracts/user_context/registration_contract_spec.rb b/spec/auction_fun_core/contracts/user_context/registration_contract_spec.rb
new file mode 100644
index 0000000..84a17d3
--- /dev/null
+++ b/spec/auction_fun_core/contracts/user_context/registration_contract_spec.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe AuctionFunCore::Contracts::UserContext::RegistrationContract, type: :contract do
+  describe "#call" do
+    subject(:contract) { described_class.new.call(attributes) }
+
+    context "when params are blank" do
+      let(:attributes) { Dry::Core::Constants::EMPTY_HASH }
+
+      it "expect failure with error messages" do
+        expect(contract).to be_failure
+        expect(contract.errors[:name]).to include(I18n.t("contracts.errors.key?"))
+        expect(contract.errors[:email]).to include(I18n.t("contracts.errors.key?"))
+        expect(contract.errors[:phone]).to include(I18n.t("contracts.errors.key?"))
+        expect(contract.errors[:password]).to include(I18n.t("contracts.errors.key?"))
+      end
+    end
+
+    it_behaves_like "validate_name_contract", :user
+    it_behaves_like "validate_email_contract", :user
+    it_behaves_like "validate_phone_contract", :user
+    it_behaves_like "validate_password_contract", :user
+    it_behaves_like "validate_password_confirmation_contract", :user
+  end
+end
diff --git a/spec/auction_fun_core/operations/user_context/registration_operation_spec.rb b/spec/auction_fun_core/operations/user_context/registration_operation_spec.rb
new file mode 100644
index 0000000..e5b6e88
--- /dev/null
+++ b/spec/auction_fun_core/operations/user_context/registration_operation_spec.rb
@@ -0,0 +1,95 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe AuctionFunCore::Operations::UserContext::RegistrationOperation, type: :operation do
+  let(:user_repository) { AuctionFunCore::Repos::UserContext::UserRepository.new }
+
+  describe ".call(attributes, &block)" do
+    let(:operation) { described_class }
+
+    context "when block is given" do
+      context "when operation happens with success" do
+        let(:attributes) do
+          Factory.structs[:user]
+            .to_h
+            .except(:id, :created_at, :updated_at, :password_digest)
+            .merge!(password: "password", password_confirmation: "password")
+        end
+
+        it "expect result success matching block" do
+          matched_success = nil
+          matched_failure = nil
+
+          operation.call(attributes) do |o|
+            o.success { |v| matched_success = v }
+            o.failure { |f| matched_failure = f }
+          end
+
+          expect(matched_success).to be_a(AuctionFunCore::Entities::User)
+          expect(matched_failure).to be_nil
+        end
+      end
+
+      context "when operation happens with failure" do
+        let(:attributes) { Dry::Core::Constants::EMPTY_HASH }
+
+        it "expect result matching block" do
+          matched_success = nil
+          matched_failure = nil
+
+          operation.call(attributes) do |o|
+            o.success { |v| matched_success = v }
+            o.failure { |f| matched_failure = f }
+          end
+
+          expect(matched_success).to be_nil
+          expect(matched_failure.errors.to_h[:name]).to include(I18n.t("contracts.errors.key?"))
+        end
+      end
+    end
+  end
+
+  describe "#call" do
+    subject(:operation) { described_class.new.call(attributes) }
+
+    context "when contract are not valid" do
+      let(:attributes) { Dry::Core::Constants::EMPTY_HASH }
+
+      it "expect not persist new user on database" do
+        expect(user_repository.count).to be_zero
+
+        expect { operation }.not_to change(user_repository, :count)
+      end
+
+      it "expect return failure with error messages" do
+        expect(operation).to be_failure
+        expect(operation.failure.errors).to be_present
+      end
+    end
+
+    context "when contract are valid" do
+      let(:attributes) do
+        Factory.structs[:user]
+          .to_h
+          .except(:id, :created_at, :updated_at, :password_digest)
+          .merge!(password: "password", password_confirmation: "password")
+      end
+
+      before do
+        allow(AuctionFunCore::Application[:event]).to receive(:publish)
+      end
+
+      it "expect persist new user on database and dispatch event registration" do
+        expect { operation }.to change(user_repository, :count).from(0).to(1)
+
+        expect(AuctionFunCore::Application[:event]).to have_received(:publish).once
+      end
+
+      it "expect return success without error messages" do
+        expect(operation).to be_success
+        expect(operation.failure).to be_blank
+      end
+    end
+  end
+end
diff --git a/spec/auction_fun_core/repos/user_context/user_repository_spec.rb b/spec/auction_fun_core/repos/user_context/user_repository_spec.rb
new file mode 100644
index 0000000..56b4f86
--- /dev/null
+++ b/spec/auction_fun_core/repos/user_context/user_repository_spec.rb
@@ -0,0 +1,117 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe AuctionFunCore::Repos::UserContext::UserRepository, type: :repo do
+  subject(:repo) { described_class.new }
+
+  describe "#create" do
+    let(:attributes) { Factory.structs[:user] }
+
+    let(:user) do
+      repo.create(
+        name: attributes.name,
+        email: attributes.email,
+        phone: attributes.phone,
+        password_digest: BCrypt::Password.create("password")
+      )
+    end
+
+    it "expect create a new auction on repository" do
+      expect(user).to be_a(AuctionFunCore::Entities::User)
+      expect(user.name).to eq(attributes.name)
+      expect(user.email).to eq(attributes.email)
+      expect(user.phone).to eq(attributes.phone)
+      expect(user.password_digest).to be_present
+      expect(user.created_at).not_to be_blank
+      expect(user.updated_at).not_to be_blank
+    end
+  end
+
+  describe "#update" do
+    let(:user) { Factory[:user] }
+    let(:new_name) { "New name" }
+
+    it "expect update user on repository" do
+      expect { repo.update(user.id, name: new_name) }
+        .to change { repo.by_id(user.id).name }
+        .from(user.name)
+        .to(new_name)
+    end
+  end
+
+  describe "#delete" do
+    let!(:user) { Factory[:user] }
+
+    it "expect remove user on repository" do
+      expect { repo.delete(user.id) }
+        .to change(repo, :count)
+        .from(1).to(0)
+    end
+  end
+
+  describe "#all" do
+    let!(:user) { Factory[:user] }
+
+    it "expect return all users" do
+      expect(repo.all.size).to eq(1)
+      expect(repo.all.first.id).to eq(user.id)
+    end
+  end
+
+  describe "#count" do
+    context "when has not user on repository" do
+      it "expect return zero" do
+        expect(repo.count).to be_zero
+      end
+    end
+
+    context "when has users on repository" do
+      let!(:auction) { Factory[:user] }
+
+      it "expect return total" do
+        expect(repo.count).to eq(1)
+      end
+    end
+  end
+
+  describe "#query(conditions)" do
+    let(:conditions) { {active: true} }
+
+    it "expect add sql conditions in query" do
+      expect(repo.query(conditions).dataset.sql).to include('WHERE ("active" IS TRUE)')
+    end
+  end
+
+  describe "#by_id(id)" do
+    context "when id is founded on repository" do
+      let!(:user) { Factory[:user] }
+
+      it "expect return rom object" do
+        expect(repo.by_id(user.id)).to be_a(AuctionFunCore::Entities::User)
+      end
+    end
+
+    context "when id is not found on repository" do
+      it "expect return nil" do
+        expect(repo.by_id(nil)).to be_nil
+      end
+    end
+  end
+
+  describe "#by_id!(id)" do
+    context "when id is founded on repository" do
+      let!(:user) { Factory[:user] }
+
+      it "expect return rom object" do
+        expect(repo.by_id(user.id)).to be_a(AuctionFunCore::Entities::User)
+      end
+    end
+
+    context "when id is not found on repository" do
+      it "expect raise exception" do
+        expect { repo.by_id!(nil) }.to raise_error(ROM::TupleCountMismatchError)
+      end
+    end
+  end
+end
diff --git a/spec/auction_fun_core_spec.rb b/spec/auction_fun_core_spec.rb
index 8b58d01..25d76a9 100644
--- a/spec/auction_fun_core_spec.rb
+++ b/spec/auction_fun_core_spec.rb
@@ -2,6 +2,6 @@
 
 RSpec.describe AuctionFunCore do
   it "has a version number" do
-    expect(AuctionFunCore::VERSION).not_to be nil
+    expect(AuctionFunCore::VERSION).to eq("0.2.0")
   end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 9c2bfce..7615df1 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,21 +1,27 @@
 # frozen_string_literal: true
 
-ENV['APP_ENV'] = 'test'
+ENV["APP_ENV"] = "test"
 
-if ENV['CI']
-  require 'simplecov'
+if ENV["CI"]
+  require "simplecov"
   SimpleCov.start do
-    add_filter '/spec'
-    add_group 'System', 'system'
-    add_group 'Config', 'config'
+    add_filter "/spec"
+    add_group "Commands", "lib/auction_fun_core/commands"
+    add_group "Contracts", "lib/auction_fun_core/contracts"
+    add_group "Entities", "lib/auction_fun_core/entities"
+    add_group "Operations", "lib/auction_fun_core/operations"
+    add_group "Relations", "lib/auction_fun_core/relations"
+    add_group "Repositories", "lib/auction_fun_core/repos"
+    add_group "System", "system"
+    add_group "Config", "config"
   end
 end
 
-require_relative '../config/application'
-require 'pry'
-require 'dotenv'
-require 'rom-factory'
-require 'database_cleaner/sequel'
+require_relative "../config/application"
+require "pry"
+require "dotenv"
+require "rom-factory"
+require "database_cleaner/sequel"
 
 AuctionFunCore::Application.start(:core)
 
@@ -38,4 +44,14 @@
   config.expect_with :rspec do |c|
     c.syntax = :expect
   end
+
+  config.before do
+    DatabaseCleaner.clean
+  end
+
+  config.after(:suite) do
+    AuctionFunCore::Application.stop(:core)
+  end
 end
+
+DatabaseCleaner.strategy = :truncation
diff --git a/spec/support/factories/users.rb b/spec/support/factories/users.rb
new file mode 100644
index 0000000..2eda793
--- /dev/null
+++ b/spec/support/factories/users.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+Factory.define(:user) do |f|
+  f.name { fake(:name, :name) }
+  f.email { fake(:internet, :email) }
+  f.phone { fake(:phone_number, :cell_phone_in_e164).tr_s("^0-9", "") }
+  f.password_digest { BCrypt::Password.create("password") }
+
+  f.trait :disabled do |t|
+    t.active { false }
+  end
+end
diff --git a/spec/support/shared_examples/validate_email_contract.rb b/spec/support/shared_examples/validate_email_contract.rb
new file mode 100644
index 0000000..ac835a6
--- /dev/null
+++ b/spec/support/shared_examples/validate_email_contract.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+shared_examples "validate_email_contract" do |factory_name|
+  let(:factory) { Factory[factory_name] }
+
+  context "when email is in wrong format" do
+    let(:attributes) { {email: "wrongemail"} }
+
+    it "expect failure with error messages" do
+      expect(subject).to be_failure
+
+      expect(subject.errors[:email]).to include(I18n.t("contracts.errors.custom.macro.email_format"))
+    end
+  end
+
+  context "when email is already exists on database" do
+    let(:attributes) { {email: factory.email} }
+
+    it "expect failure with error messages" do
+      expect(subject).to be_failure
+
+      expect(subject.errors[:email]).to include(I18n.t("contracts.errors.custom.default.taken"))
+    end
+  end
+end
diff --git a/spec/support/shared_examples/validate_name_contract.rb b/spec/support/shared_examples/validate_name_contract.rb
new file mode 100644
index 0000000..8c6121b
--- /dev/null
+++ b/spec/support/shared_examples/validate_name_contract.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+shared_examples "validate_name_contract" do |factory_name|
+  let(:min) { AuctionFunCore::Contracts::ApplicationContract::MIN_NAME_LENGTH }
+  let(:max) { AuctionFunCore::Contracts::ApplicationContract::MAX_NAME_LENGTH }
+  let(:factory) { Factory[factory_name] }
+
+  context "when the characters in the name are outside the allowed range" do
+    let(:attributes) { {name: "abc"} }
+
+    it "expect failure with error messages" do
+      expect(subject).to be_failure
+
+      expect(subject.errors[:name]).to include(
+        I18n.t("contracts.errors.custom.macro.name_format", min: min, max: max)
+      )
+    end
+  end
+end
diff --git a/spec/support/shared_examples/validate_password_confirmation_contract.rb b/spec/support/shared_examples/validate_password_confirmation_contract.rb
new file mode 100644
index 0000000..a5e2827
--- /dev/null
+++ b/spec/support/shared_examples/validate_password_confirmation_contract.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+shared_examples "validate_password_confirmation_contract" do |factory_name|
+  let(:factory) { Factory[factory_name] }
+
+  context "when password characters are outside the allowed range" do
+    let(:attributes) { {password: "password", password_confirmation: "1234567"} }
+
+    it "expect failure with error messages" do
+      expect(contract).to be_failure
+      expect(contract.errors[:password_confirmation]).to include(
+        I18n.t("contracts.errors.custom.default.password_confirmation")
+      )
+    end
+  end
+end
diff --git a/spec/support/shared_examples/validate_password_contract.rb b/spec/support/shared_examples/validate_password_contract.rb
new file mode 100644
index 0000000..6e838d1
--- /dev/null
+++ b/spec/support/shared_examples/validate_password_contract.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+shared_examples "validate_password_contract" do |factory_name|
+  let(:min) { AuctionFunCore::Contracts::ApplicationContract::MIN_PASSWORD_LENGTH }
+  let(:max) { AuctionFunCore::Contracts::ApplicationContract::MAX_PASSWORD_LENGTH }
+  let(:factory) { Factory[factory_name] }
+
+  context "when password characters are outside the allowed range" do
+    let(:attributes) { {password: "123", password_confirmation: "123"} }
+
+    it "expect failure with error messages" do
+      expect(contract).to be_failure
+      expect(contract.errors[:password]).to include(
+        I18n.t("contracts.errors.custom.macro.password_format", min: min, max: max)
+      )
+    end
+  end
+end
diff --git a/spec/support/shared_examples/validate_phone_contract.rb b/spec/support/shared_examples/validate_phone_contract.rb
new file mode 100644
index 0000000..df80c36
--- /dev/null
+++ b/spec/support/shared_examples/validate_phone_contract.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+shared_examples "validate_phone_contract" do |factory_name|
+  let(:factory) { Factory[factory_name] }
+
+  context "when phone is in wrong format" do
+    let(:attributes) { {phone: "12345"} }
+
+    it "expect failure with error messages" do
+      expect(subject).to be_failure
+
+      expect(subject.errors[:phone]).to include(I18n.t("contracts.errors.custom.macro.phone_format"))
+    end
+  end
+
+  context "when phone is already exists on database" do
+    let(:attributes) { {phone: factory.phone} }
+
+    it "expect failure with error messages" do
+      expect(subject).to be_failure
+
+      expect(subject.errors[:phone]).to include(I18n.t("contracts.errors.custom.default.taken"))
+    end
+  end
+end
diff --git a/system/providers/core.rb b/system/providers/core.rb
index bad627a..59f22c5 100644
--- a/system/providers/core.rb
+++ b/system/providers/core.rb
@@ -3,15 +3,13 @@
 # This file load requirements to main API.
 AuctionFunCore::Application.register_provider(:core) do
   prepare do
-    require 'dry/validation'
-    require 'dry/monads/all'
-    require 'dry/matcher/result_matcher'
-    require 'dry/events'
-  end
-
-  start do
-    target.start(:settings)
-    target.start(:persistence)
+    require "dry/validation"
+    require "dry/monads/all"
+    require "dry/matcher/result_matcher"
+    require "active_support"
+    require "active_support/core_ext/object/blank"
+    require "active_support/time"
+    require "dry/events"
 
     Dry::Schema.load_extensions(:hints)
     Dry::Schema.load_extensions(:info)
@@ -19,4 +17,18 @@
     Dry::Validation.load_extensions(:monads)
     Dry::Types.load_extensions(:monads)
   end
+
+  start do
+    target.start(:settings)
+    target.start(:events)
+    target.start(:logger)
+    target.start(:persistence)
+  end
+
+  stop do
+    target.stop(:settings)
+    target.stop(:events)
+    target.stop(:logger)
+    target.stop(:persistence)
+  end
 end
diff --git a/system/providers/db.rb b/system/providers/db.rb
index 903a344..128e2d7 100644
--- a/system/providers/db.rb
+++ b/system/providers/db.rb
@@ -4,8 +4,8 @@
 # and registers it with our application under the container key.
 AuctionFunCore::Application.register_provider(:db) do
   prepare do
-    require 'rom'
-    require 'rom-sql'
+    require "rom"
+    require "rom-sql"
   end
 
   start do
@@ -14,13 +14,13 @@
       extensions: %i[pg_array pg_json pg_enum]
     )
     migrator = ROM::SQL::Migration::Migrator.new(
-      connection, path: Pathname.new(AuctionFunCore::Application.root.join('db/migrate'))
+      connection, path: Pathname.new(AuctionFunCore::Application.root.join("db/migrate"))
     )
     register(:db_connection, connection)
     register(:db_config, ROM::Configuration.new(:sql, connection, migrator: migrator))
   end
 
   stop do
-    container['db_connection'].disconnect
+    container["db_connection"].disconnect
   end
 end
diff --git a/system/providers/events.rb b/system/providers/events.rb
new file mode 100644
index 0000000..ad52693
--- /dev/null
+++ b/system/providers/events.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+AuctionFunCore::Application.register_provider(:events) do
+  start do
+    register(:event, AuctionFunCore::Events::App.new)
+    register(:listener, AuctionFunCore::Events::Listener.new)
+    register(:subscription, event.subscribe(listener))
+  end
+
+  stop do
+    container["subscription"].unsubscribe(listener)
+  end
+end
diff --git a/system/providers/logger.rb b/system/providers/logger.rb
new file mode 100644
index 0000000..bfa896e
--- /dev/null
+++ b/system/providers/logger.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+AuctionFunCore::Application.register_provider(:logger) do
+  prepare do
+    require "logger"
+  end
+
+  start do
+    register(:logger, AuctionFunCore::Application[:settings].logger)
+  end
+end
diff --git a/system/providers/persistence.rb b/system/providers/persistence.rb
index 8dda44b..577aed7 100644
--- a/system/providers/persistence.rb
+++ b/system/providers/persistence.rb
@@ -4,8 +4,8 @@
 # and registers it with our application under the container key.
 AuctionFunCore::Application.register_provider(:persistence) do
   prepare do
-    require 'rom'
-    require 'rom-sql'
+    require "rom"
+    require "rom-sql"
   end
 
   start do
diff --git a/system/providers/settings.rb b/system/providers/settings.rb
index eacd1e9..c80a3db 100644
--- a/system/providers/settings.rb
+++ b/system/providers/settings.rb
@@ -1,15 +1,19 @@
 # frozen_string_literal: true
 
-require 'dry/system/provider_sources'
+require "dry/system/provider_sources"
 
 # This file uses the rom gem to define a database configuration container
 # and registers it with our application under the container key.
 AuctionFunCore::Application.register_provider(:settings, from: :dry_system) do
   before :prepare do
-    require 'money'
+    require "money"
   end
 
   settings do
-    setting :database_url, constructor: Dry::Types['string'].constrained(filled: true)
+    setting :database_url, constructor: Dry::Types["string"].constrained(filled: true)
+    setting :logger, default: Logger.new($stdout)
+    setting :logger_level, default: :info, constructor: Dry::Types["symbol"]
+      .constructor { |value| value.to_s.downcase.to_sym }
+      .enum(:trace, :unknown, :error, :fatal, :warn, :info, :debug)
   end
 end