diff --git a/lecture_5/homework/.rspec b/lecture_5/homework/.rspec
new file mode 100644
index 00000000..c99d2e73
--- /dev/null
+++ b/lecture_5/homework/.rspec
@@ -0,0 +1 @@
+--require spec_helper
diff --git a/lecture_5/homework/Gemfile b/lecture_5/homework/Gemfile
index f10bbf07..d3db0ff7 100644
--- a/lecture_5/homework/Gemfile
+++ b/lecture_5/homework/Gemfile
@@ -5,6 +5,9 @@ git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
 ruby '2.6.2'
 
+gem 'factory_bot_rails'
+gem 'faker'
+gem 'rubocop-rspec'
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 5.2.2'
 # Use pg as the database for Active Record
diff --git a/lecture_5/homework/Gemfile.lock b/lecture_5/homework/Gemfile.lock
index 411593e8..eaa3512c 100644
--- a/lecture_5/homework/Gemfile.lock
+++ b/lecture_5/homework/Gemfile.lock
@@ -1,25 +1,25 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    actioncable (5.2.2.1)
-      actionpack (= 5.2.2.1)
+    actioncable (5.2.3)
+      actionpack (= 5.2.3)
       nio4r (~> 2.0)
       websocket-driver (>= 0.6.1)
-    actionmailer (5.2.2.1)
-      actionpack (= 5.2.2.1)
-      actionview (= 5.2.2.1)
-      activejob (= 5.2.2.1)
+    actionmailer (5.2.3)
+      actionpack (= 5.2.3)
+      actionview (= 5.2.3)
+      activejob (= 5.2.3)
       mail (~> 2.5, >= 2.5.4)
       rails-dom-testing (~> 2.0)
-    actionpack (5.2.2.1)
-      actionview (= 5.2.2.1)
-      activesupport (= 5.2.2.1)
+    actionpack (5.2.3)
+      actionview (= 5.2.3)
+      activesupport (= 5.2.3)
       rack (~> 2.0)
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (5.2.2.1)
-      activesupport (= 5.2.2.1)
+    actionview (5.2.3)
+      activesupport (= 5.2.3)
       builder (~> 3.1)
       erubi (~> 1.4)
       rails-dom-testing (~> 2.0)
@@ -29,36 +29,43 @@ GEM
       activemodel (>= 4.1, < 6)
       case_transform (>= 0.2)
       jsonapi-renderer (>= 0.1.1.beta1, < 0.3)
-    activejob (5.2.2.1)
-      activesupport (= 5.2.2.1)
+    activejob (5.2.3)
+      activesupport (= 5.2.3)
       globalid (>= 0.3.6)
-    activemodel (5.2.2.1)
-      activesupport (= 5.2.2.1)
-    activerecord (5.2.2.1)
-      activemodel (= 5.2.2.1)
-      activesupport (= 5.2.2.1)
+    activemodel (5.2.3)
+      activesupport (= 5.2.3)
+    activerecord (5.2.3)
+      activemodel (= 5.2.3)
+      activesupport (= 5.2.3)
       arel (>= 9.0)
-    activestorage (5.2.2.1)
-      actionpack (= 5.2.2.1)
-      activerecord (= 5.2.2.1)
+    activestorage (5.2.3)
+      actionpack (= 5.2.3)
+      activerecord (= 5.2.3)
       marcel (~> 0.3.1)
-    activesupport (5.2.2.1)
+    activesupport (5.2.3)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
     arel (9.0.0)
     ast (2.4.0)
-    bootsnap (1.4.1)
+    bootsnap (1.4.3)
       msgpack (~> 1.0)
     builder (3.2.3)
-    byebug (11.0.0)
+    byebug (11.0.1)
     case_transform (0.2)
       activesupport
     concurrent-ruby (1.1.5)
     crass (1.0.4)
     diff-lcs (1.3)
     erubi (1.8.0)
+    factory_bot (5.0.2)
+      activesupport (>= 4.2.0)
+    factory_bot_rails (5.0.2)
+      factory_bot (~> 5.0.2)
+      railties (>= 4.2.0)
+    faker (1.9.3)
+      i18n (>= 0.7)
     ffi (1.10.0)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
@@ -84,38 +91,38 @@ GEM
     minitest (5.11.3)
     msgpack (1.2.9)
     nio4r (2.3.1)
-    nokogiri (1.10.1)
+    nokogiri (1.10.2)
       mini_portile2 (~> 2.4.0)
     parallel (1.17.0)
-    parser (2.6.2.0)
+    parser (2.6.2.1)
       ast (~> 2.4.0)
     pg (1.1.4)
     psych (3.1.0)
-    puma (3.12.0)
-    rack (2.0.6)
+    puma (3.12.1)
+    rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
-    rails (5.2.2.1)
-      actioncable (= 5.2.2.1)
-      actionmailer (= 5.2.2.1)
-      actionpack (= 5.2.2.1)
-      actionview (= 5.2.2.1)
-      activejob (= 5.2.2.1)
-      activemodel (= 5.2.2.1)
-      activerecord (= 5.2.2.1)
-      activestorage (= 5.2.2.1)
-      activesupport (= 5.2.2.1)
+    rails (5.2.3)
+      actioncable (= 5.2.3)
+      actionmailer (= 5.2.3)
+      actionpack (= 5.2.3)
+      actionview (= 5.2.3)
+      activejob (= 5.2.3)
+      activemodel (= 5.2.3)
+      activerecord (= 5.2.3)
+      activestorage (= 5.2.3)
+      activesupport (= 5.2.3)
       bundler (>= 1.3.0)
-      railties (= 5.2.2.1)
+      railties (= 5.2.3)
       sprockets-rails (>= 2.0.0)
     rails-dom-testing (2.0.3)
       activesupport (>= 4.2.0)
       nokogiri (>= 1.6)
     rails-html-sanitizer (1.0.4)
       loofah (~> 2.2, >= 2.2.2)
-    railties (5.2.2.1)
-      actionpack (= 5.2.2.1)
-      activesupport (= 5.2.2.1)
+    railties (5.2.3)
+      actionpack (= 5.2.3)
+      activesupport (= 5.2.3)
       method_source
       rake (>= 0.8.7)
       thor (>= 0.19.0, < 2.0)
@@ -149,6 +156,8 @@ GEM
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 1.6)
+    rubocop-rspec (1.32.0)
+      rubocop (>= 0.60.0)
     ruby-progressbar (1.10.0)
     ruby_dep (1.5.0)
     spring (2.0.2)
@@ -179,12 +188,15 @@ DEPENDENCIES
   active_model_serializers
   bootsnap (>= 1.1.0)
   byebug
+  factory_bot_rails
+  faker
   listen (>= 3.0.5, < 3.2)
   pg
   puma (~> 3.11)
   rails (~> 5.2.2)
   rspec-rails
   rubocop
+  rubocop-rspec
   spring
   spring-watcher-listen (~> 2.0.0)
   tzinfo-data
diff --git a/lecture_5/homework/app/controllers/buildings_controller.rb b/lecture_5/homework/app/controllers/buildings_controller.rb
index 9b7e9677..da3a2239 100644
--- a/lecture_5/homework/app/controllers/buildings_controller.rb
+++ b/lecture_5/homework/app/controllers/buildings_controller.rb
@@ -1,7 +1,21 @@
 # frozen_string_literal: true
 
 class BuildingsController < ApplicationController
-  def index; end
+  def index
+    render json: Building.all.order(:id), include: [:warriors]
+  end
 
-  def show; end
+  def show
+    render json: building, include: [:warriors]
+  end
+
+  private
+
+  def build_params
+    params.permit(:name,:granary)
+  end
+
+  def building
+    @building ||= Building.find(params[:id])
+  end
 end
diff --git a/lecture_5/homework/app/models/building.rb b/lecture_5/homework/app/models/building.rb
index ee460ad6..f165f041 100644
--- a/lecture_5/homework/app/models/building.rb
+++ b/lecture_5/homework/app/models/building.rb
@@ -4,5 +4,6 @@ class Building < ApplicationRecord
   has_many :warriors, dependent: :nullify
 
   validates :granary, presence: true,
-                      numerically: { greater_than_or_equal_to: 0, only_integer: true }
+                      numericality: { greater_than_or_equal_to: 0, only_integer: true }
+  validates :siege_ability, presence: true, numericality: { greater_than_or_equal_to: 0 }
 end
diff --git a/lecture_5/homework/app/models/warrior.rb b/lecture_5/homework/app/models/warrior.rb
index eacdc13f..fe16b77d 100644
--- a/lecture_5/homework/app/models/warrior.rb
+++ b/lecture_5/homework/app/models/warrior.rb
@@ -14,4 +14,41 @@ class Warrior < ApplicationRecord
 
   scope :alive, -> { where('death_date IS NULL') }
   scope :dead, -> { where('death_date IS NOT NULL') }
+
+  after_create :update_siege
+  before_update :update_prev_building
+  # cant put same if: :building_id_changed?  since it will always return false
+  after_update  :update_siege_after
+  # after_commit :update_siege_after
+  after_destroy :update_siege
+
+  def update_siege
+    # call after warrior already was asigned to building list after create,update
+    # works for delete as well
+    Reports::SiegeReport.call(building: building) if building
+  end
+
+  # it seems like rspec didnt invoke those callbacks
+  # when i was testing manually it works
+  # probably messed up in factory and tests :(
+  def update_siege_after
+    if prev_building_id
+      # if warrior changed his building run this on both
+      # since in that moment he is no longer in old list , rather in new building
+      # so this way i can keep both old and new buildings updated
+      # puts "prev building: #{prev_building_id} current: #{building_id}"
+      Reports::SiegeReport.call(building: Building.find(prev_building_id))
+      Reports::SiegeReport.call(building: Building.find(building_id))
+      # set this to nil to prevent callback invoking from random update
+      update_column(:prev_building_id, nil)
+    end
+  end
+
+  def update_prev_building
+    # if warrior is changing his buildings
+    if building_id_was != building_id
+      # save this attribute wihtout triggering callbacks
+      update_column(:prev_building_id, building_id_was)
+    end
+  end
 end
diff --git a/lecture_5/homework/app/serializers/building_serializer.rb b/lecture_5/homework/app/serializers/building_serializer.rb
index 899c9aa0..784d9e97 100644
--- a/lecture_5/homework/app/serializers/building_serializer.rb
+++ b/lecture_5/homework/app/serializers/building_serializer.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 class BuildingSerializer < ActiveModel::Serializer
-  attributes :name
+  attributes :name, :siege_ability, :granary
 
   has_many :warriors
 end
diff --git a/lecture_5/homework/app/services/reports/siege_report.rb b/lecture_5/homework/app/services/reports/siege_report.rb
index 16a0b3a4..5b5b9fec 100644
--- a/lecture_5/homework/app/services/reports/siege_report.rb
+++ b/lecture_5/homework/app/services/reports/siege_report.rb
@@ -2,11 +2,21 @@
 
 module Reports
   class SiegeReport
-    def initialize(building:)
-    end
+    def self.call(building:)
+      # this should stop the method if getting null
+      return unless building
 
-    def call
-      raise NotImprementedYet
+      # bulding cant be defended without warriors
+      if building.warriors.any?
+        warriors_count = building.warriors.where(type: 'Warriors::Samurai').count
+        hussar_count = building.warriors.where(type: 'Warriors::Hussar').count
+        total_rice_need = warriors_count + hussar_count * 2 + building.default_rice_need
+        siege_ability = building.granary / total_rice_need
+        building.siege_ability = siege_ability
+      else
+        building.siege_ability = 0
+      end
+      building.save!
     end
   end
 end
diff --git a/lecture_5/homework/db/migrate/20190415130731_add_siege_ability.rb b/lecture_5/homework/db/migrate/20190415130731_add_siege_ability.rb
new file mode 100644
index 00000000..1affa82b
--- /dev/null
+++ b/lecture_5/homework/db/migrate/20190415130731_add_siege_ability.rb
@@ -0,0 +1,6 @@
+class AddSiegeAbility < ActiveRecord::Migration[5.2]
+  def change
+    add_column :buildings, :siege_ability, :integer, default: 0, null: false
+
+  end
+end
diff --git a/lecture_5/homework/db/migrate/20190415133246_add_default_rice_need.rb b/lecture_5/homework/db/migrate/20190415133246_add_default_rice_need.rb
new file mode 100644
index 00000000..84e04edd
--- /dev/null
+++ b/lecture_5/homework/db/migrate/20190415133246_add_default_rice_need.rb
@@ -0,0 +1,8 @@
+class AddDefaultRiceNeed < ActiveRecord::Migration[5.2]
+  def change
+    add_column :buildings, :default_rice_need, :integer, default: 0
+       
+    Buildings::Stronghold.find_each { |building| update_attribute(:default_rice_need,10) }
+    Building.find_each { |building| Reports::SiegeReport.check_siege_ability(building: building) }
+  end
+end
diff --git a/lecture_5/homework/db/migrate/20190417075546_add_previous_building_id.rb b/lecture_5/homework/db/migrate/20190417075546_add_previous_building_id.rb
new file mode 100644
index 00000000..09719822
--- /dev/null
+++ b/lecture_5/homework/db/migrate/20190417075546_add_previous_building_id.rb
@@ -0,0 +1,6 @@
+class AddPreviousBuildingId < ActiveRecord::Migration[5.2]
+  def change
+    add_column :warriors, :prev_building_id, :integer
+    
+  end
+end
diff --git a/lecture_5/homework/db/schema.rb b/lecture_5/homework/db/schema.rb
index 13f968ab..725af4c9 100644
--- a/lecture_5/homework/db/schema.rb
+++ b/lecture_5/homework/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2019_04_05_090544) do
+ActiveRecord::Schema.define(version: 2019_04_17_075546) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -20,6 +20,9 @@
     t.string "type", null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.integer "granary", default: 0, null: false
+    t.integer "siege_ability", default: 0, null: false
+    t.integer "default_rice_need", default: 0
   end
 
   create_table "clans", force: :cascade do |t|
@@ -53,6 +56,7 @@
     t.string "type", default: "Warriors::Samurai", null: false
     t.bigint "building_id"
     t.string "preferred_weapon_kind"
+    t.integer "prev_building_id"
     t.index ["building_id"], name: "index_warriors_on_building_id"
     t.index ["clan_id"], name: "index_warriors_on_clan_id"
     t.index ["name"], name: "index_warriors_on_name", unique: true, where: "(death_date IS NULL)"
diff --git a/lecture_5/homework/db/seeds.rb b/lecture_5/homework/db/seeds.rb
index 66a120fd..d44633c5 100644
--- a/lecture_5/homework/db/seeds.rb
+++ b/lecture_5/homework/db/seeds.rb
@@ -3,13 +3,15 @@
 first_clan = Clan.create!(name: 'The very first clan')
 training_clan = Clan.create!(name: 'Training clan')
 
-stronghold = Buildings::Stronghold.create!(name: 'Main stronghold', granary: 5000)
+stronghold = Buildings::Stronghold.create!(name: 'Main stronghold', granary: 5000,default_rice_need: 10)
+stronghold_empty = Buildings::Stronghold.create!(name: 'Empty stronghold', granary: 5000,default_rice_need: 10)
 northern_wall = Buildings::Walls.create!(name: 'Northern wall', granary: 100)
 southern_wall = Buildings::Walls.create!(name: 'Southern wall', granary: 100)
 
 samurai_1 = Warriors::Samurai.create!(name: '曽山大輝', clan: first_clan, death_date: 1.week.ago)
 samurai_2 = Warriors::Samurai.create!(name: '曽山大輝', clan: first_clan, building: stronghold)
 samurai_3 = Warriors::Samurai.create!(name: '澄田清', clan: training_clan, building: stronghold)
+hussar_4 = Warriors::Hussar.create!(name: 'Banzai Hito', clan: first_clan, building: stronghold)
 hussar_1 = Warriors::Hussar.create!(name: 'Idzi Kwiatkowski', clan: first_clan, building: northern_wall)
 hussar_2 = Warriors::Hussar.create!(name: 'Świętopełk Król', clan: training_clan, building: southern_wall)
 
diff --git a/lecture_5/homework/spec/controllers/buildings_controller_spec.rb b/lecture_5/homework/spec/controllers/buildings_controller_spec.rb
new file mode 100644
index 00000000..396298cd
--- /dev/null
+++ b/lecture_5/homework/spec/controllers/buildings_controller_spec.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe BuildingsController, type: :controller do
+  subject(:building) { create(:building) } 
+  describe 'it get all buildings' do
+    it 'responds with 200' do
+      get 'index'
+      expect(response).to have_http_status(200)
+    end
+  end
+
+  describe 'it should find some building' do
+    it 'responds with 200' do
+      get :show, params: { id: building.id }
+      expect(response).to have_http_status(200)
+    end
+  end
+
+  describe 'it shows no building found' do
+    it 'responds with 404' do
+      get :show, params: { id: 999 }
+      expect(response).to have_http_status(404)
+    end
+  end
+end
diff --git a/lecture_5/homework/spec/factories/buildings.rb b/lecture_5/homework/spec/factories/buildings.rb
new file mode 100644
index 00000000..c24cde60
--- /dev/null
+++ b/lecture_5/homework/spec/factories/buildings.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :building do
+    name { Faker::Games::Witcher.location }
+    type { 'Buildings::Walls' }
+    granary { 500 }
+  end
+end
diff --git a/lecture_5/homework/spec/factories/clans.rb b/lecture_5/homework/spec/factories/clans.rb
new file mode 100644
index 00000000..91af847e
--- /dev/null
+++ b/lecture_5/homework/spec/factories/clans.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :clan do
+    name { Faker::Games::Witcher.school }
+  end
+end
diff --git a/lecture_5/homework/spec/factories/warrior.rb b/lecture_5/homework/spec/factories/warrior.rb
new file mode 100644
index 00000000..5efc9263
--- /dev/null
+++ b/lecture_5/homework/spec/factories/warrior.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :warrior do
+    name  { Faker::Games::Witcher.character }
+    association :building
+    association :clan
+
+    trait :samurai do
+      type { 'Warriors::Samurai' }
+    end
+
+    trait :hussar do
+      type { 'Warriors::Hussar' }
+    end
+  end
+end
diff --git a/lecture_5/homework/spec/helpers/reports/siege_report_spec.rb b/lecture_5/homework/spec/helpers/reports/siege_report_spec.rb
new file mode 100644
index 00000000..7da417b0
--- /dev/null
+++ b/lecture_5/homework/spec/helpers/reports/siege_report_spec.rb
@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Reports::SiegeReport, type: :helper do
+  subject(:clan) { create(:clan) }
+  subject(:building) { create(:building) }
+  subject(:building2) { create(:building) }
+  context(' valid data ') do
+    it 'set building siege_value to be 250' do
+      w1 = create(:warrior, :samurai, clan: clan, building: building)
+      w2 = create(:warrior, :samurai, clan: clan, building: building)
+      # Reports::SiegeReport.call(building: building)
+      expect(building.siege_ability).to eq(250)
+    end
+
+    it 'set building siege_value to be 500 after one warrior was destroyed' do
+      w1 = create(:warrior, :samurai, clan: clan, building: building)
+      w2 = create(:warrior, :samurai, clan: clan, building: building)
+      # Reports::SiegeReport.call(building: building)
+      w2.destroy!
+      expect(building.siege_ability).to eq(500)
+    end
+
+    it 'set building siege_value to be 0 after both warriors was destroyed' do
+      w1 = create(:warrior, :samurai, clan: clan, building: building)
+      w2 = create(:warrior, :samurai, clan: clan, building: building)
+      # Reports::SiegeReport.call(building: building)
+      w1.destroy
+      w2.destroy
+      expect(building.siege_ability).to eq(0)
+    end
+
+    # fail should 500 instead of 250
+    it 'set building siege_value to be 250 after building change' do
+      w1 = create(:warrior, :samurai, clan: clan, building: building)
+      w2 = create(:warrior, :samurai, clan: clan, building: building2)
+      Reports::SiegeReport.call(building: building)
+      w2.update(building: building)
+      expect(building.siege_ability).to eq(500)
+    end
+
+    # Fail got 250 instead of 500
+    it 'set building siege_value to be 500 after building change' do
+      w1 = create(:warrior, :samurai, clan: clan, building: building)
+      w2 = create(:warrior, :samurai, clan: clan, building: building)
+      Reports::SiegeReport.call(building: building)
+      w2.update!(building: building2)
+
+      expect(building.siege_ability).to eq(250)
+    end
+    # Fail got 500 instead of 0
+    it 'set building siege_value to be 0 after building2 change' do
+      w1 = create(:warrior, :samurai, clan: clan, building: building)
+      w2 = create(:warrior, :samurai, clan: clan, building: building2)
+      Reports::SiegeReport.call(building: building)
+      w2.update!(building: building)
+      expect(building2.siege_ability).to eq(500)
+    end
+  end
+
+  context(' invalid data ') do
+    it 'should return nothing' do
+      expect(Reports::SiegeReport.call(building: nil)).to be_nil
+    end
+
+    it 'should set building to 0 siege_ability' do
+      Reports::SiegeReport.call(building: building)
+      expect(building.siege_ability).to eq(0)
+    end
+  end
+end
diff --git a/lecture_5/homework/spec/rails_helper.rb b/lecture_5/homework/spec/rails_helper.rb
new file mode 100644
index 00000000..e2cb8518
--- /dev/null
+++ b/lecture_5/homework/spec/rails_helper.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+# This file is copied to spec/ when you run 'rails generate rspec:install'
+require 'spec_helper'
+ENV['RAILS_ENV'] ||= 'test'
+require File.expand_path('../config/environment', __dir__)
+# Prevent database truncation if the environment is production
+abort('The Rails environment is running in production mode!') if Rails.env.production?
+require 'rspec/rails'
+# Add additional requires below this line. Rails is not loaded until this point!
+
+# Requires supporting ruby files with custom matchers and macros, etc, in
+# spec/support/ and its subdirectories. Files matching `spec/**/*_spec.rb` are
+# run as spec files by default. This means that files in spec/support that end
+# in _spec.rb will both be required and run as specs, causing the specs to be
+# run twice. It is recommended that you do not name files matching this glob to
+# end with _spec.rb. You can configure this pattern with the --pattern
+# option on the command line or in ~/.rspec, .rspec or `.rspec-local`.
+#
+# The following line is provided for convenience purposes. It has the downside
+# of increasing the boot-up time by auto-requiring all files in the support
+# directory. Alternatively, in the individual `*_spec.rb` files, manually
+# require only the support files necessary.
+#
+# Dir[Rails.root.join('spec', 'support', '**', '*.rb')].each { |f| require f }
+
+# Checks for pending migrations and applies them before tests are run.
+# If you are not using ActiveRecord, you can remove these lines.
+begin
+  ActiveRecord::Migration.maintain_test_schema!
+rescue ActiveRecord::PendingMigrationError => e
+  puts e.to_s.strip
+  exit 1
+end
+RSpec.configure do |config|
+  config.include FactoryBot::Syntax::Methods
+  # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
+  config.fixture_path = "#{::Rails.root}/spec/fixtures"
+
+  # If you're not using ActiveRecord, or you'd prefer not to run each of your
+  # examples within a transaction, remove the following line or assign false
+  # instead of true.
+  config.use_transactional_fixtures = true
+
+  # RSpec Rails can automatically mix in different behaviours to your tests
+  # based on their file location, for example enabling you to call `get` and
+  # `post` in specs under `spec/controllers`.
+  #
+  # You can disable this behaviour by removing the line below, and instead
+  # explicitly tag your specs with their type, e.g.:
+  #
+  #     RSpec.describe UsersController, :type => :controller do
+  #       # ...
+  #     end
+  #
+  # The different available types are documented in the features, such as in
+  # https://relishapp.com/rspec/rspec-rails/docs
+  config.infer_spec_type_from_file_location!
+
+  # Filter lines from Rails gems in backtraces.
+  config.filter_rails_from_backtrace!
+  # arbitrary gems may also be filtered via:
+  # config.filter_gems_from_backtrace("gem name")
+end
diff --git a/lecture_5/homework/spec/spec_helper.rb b/lecture_5/homework/spec/spec_helper.rb
new file mode 100644
index 00000000..01f7c974
--- /dev/null
+++ b/lecture_5/homework/spec/spec_helper.rb
@@ -0,0 +1,96 @@
+# frozen_string_literal: true
+
+# This file was generated by the `rails generate rspec:install` command. Conventionally, all
+# specs live under a `spec` directory, which RSpec adds to the `$LOAD_PATH`.
+# The generated `.rspec` file contains `--require spec_helper` which will cause
+# this file to always be loaded, without a need to explicitly require it in any
+# files.
+#
+# Given that it is always loaded, you are encouraged to keep this file as
+# light-weight as possible. Requiring heavyweight dependencies from this file
+# will add to the boot time of your test suite on EVERY test run, even for an
+# individual file that may not need all of that loaded. Instead, consider making
+# a separate helper file that requires the additional dependencies and performs
+# the additional setup, and require it from the spec files that actually need
+# it.
+#
+# See http://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
+RSpec.configure do |config|
+  # rspec-expectations config goes here. You can use an alternate
+  # assertion/expectation library such as wrong or the stdlib/minitest
+  # assertions if you prefer.
+  config.expect_with :rspec do |expectations|
+    # This option will default to `true` in RSpec 4. It makes the `description`
+    # and `failure_message` of custom matchers include text for helper methods
+    # defined using `chain`, e.g.:
+    #     be_bigger_than(2).and_smaller_than(4).description
+    #     # => "be bigger than 2 and smaller than 4"
+    # ...rather than:
+    #     # => "be bigger than 2"
+    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
+  end
+
+  # rspec-mocks config goes here. You can use an alternate test double
+  # library (such as bogus or mocha) by changing the `mock_with` option here.
+  config.mock_with :rspec do |mocks|
+    # Prevents you from mocking or stubbing a method that does not exist on
+    # a real object. This is generally recommended, and will default to
+    # `true` in RSpec 4.
+    mocks.verify_partial_doubles = true
+  end
+
+  # This option will default to `:apply_to_host_groups` in RSpec 4 (and will
+  # have no way to turn it off -- the option exists only for backwards
+  # compatibility in RSpec 3). It causes shared context metadata to be
+  # inherited by the metadata hash of host groups and examples, rather than
+  # triggering implicit auto-inclusion in groups with matching metadata.
+  config.shared_context_metadata_behavior = :apply_to_host_groups
+
+  # The settings below are suggested to provide a good initial experience
+  # with RSpec, but feel free to customize to your heart's content.
+  #   # This allows you to limit a spec run to individual examples or groups
+  #   # you care about by tagging them with `:focus` metadata. When nothing
+  #   # is tagged with `:focus`, all examples get run. RSpec also provides
+  #   # aliases for `it`, `describe`, and `context` that include `:focus`
+  #   # metadata: `fit`, `fdescribe` and `fcontext`, respectively.
+  #   config.filter_run_when_matching :focus
+  #
+  #   # Allows RSpec to persist some state between runs in order to support
+  #   # the `--only-failures` and `--next-failure` CLI options. We recommend
+  #   # you configure your source control system to ignore this file.
+  #   config.example_status_persistence_file_path = "spec/examples.txt"
+  #
+  #   # Limits the available syntax to the non-monkey patched syntax that is
+  #   # recommended. For more details, see:
+  #   #   - http://rspec.info/blog/2012/06/rspecs-new-expectation-syntax/
+  #   #   - http://www.teaisaweso.me/blog/2013/05/27/rspecs-new-message-expectation-syntax/
+  #   #   - http://rspec.info/blog/2014/05/notable-changes-in-rspec-3/#zero-monkey-patching-mode
+  #   config.disable_monkey_patching!
+  #
+  #   # Many RSpec users commonly either run the entire suite or an individual
+  #   # file, and it's useful to allow more verbose output when running an
+  #   # individual spec file.
+  #   if config.files_to_run.one?
+  #     # Use the documentation formatter for detailed output,
+  #     # unless a formatter has already been configured
+  #     # (e.g. via a command-line flag).
+  #     config.default_formatter = "doc"
+  #   end
+  #
+  #   # Print the 10 slowest examples and example groups at the
+  #   # end of the spec run, to help surface which specs are running
+  #   # particularly slow.
+  #   config.profile_examples = 10
+  #
+  #   # Run specs in random order to surface order dependencies. If you find an
+  #   # order dependency and want to debug it, you can fix the order by providing
+  #   # the seed, which is printed after each run.
+  #   #     --seed 1234
+  #   config.order = :random
+  #
+  #   # Seed global randomization in this process using the `--seed` CLI option.
+  #   # Setting this allows you to use `--seed` to deterministically reproduce
+  #   # test failures related to randomization by passing the same `--seed` value
+  #   # as the one that triggered the failure.
+  #   Kernel.srand config.seed
+end