feat(README): improve docs

README.md

@@ -3,22 +3,33 @@
 
 # any_query
 
-An ORM for any data source (SQL, CSV, TSV, REST API)
+`any_query` is a versatile ORM designed to interface with various data sources including SQL, CSV, TSV, Fixed Length Text Format, and REST APIs. With any_query, you can write SQL-like queries and receive results as ActiveRecord-like objects. It supports operations like `select`, `limit`, and even `joins` across different data sources.
+
+## Features
+* Unified Query Language: Write SQL-like queries for any supported data source.
+* ActiveRecord-like Objects: Get results in a familiar format.
+* Cross-data Source Joins: Combine data from different sources seamlessly.
 
 ## Installation
 
-Add the gem to your Gemfile
+To install `any_query`, add the gem to your Gemfile:
 
 ```ruby
   gem 'any_query'
 ```
 
-### Models
+Then run:
 
-Include `AnyQuery` and create adapters according to your needs:
+```bash
+  bundle install
+```
 
-```ruby
+## Usage
+### Setting up Models
+To use `any_query`, include it in your model and set up the necessary adapters:
 
+
+```ruby
 class Invoice
   include AnyQuery
 
@@ -68,7 +79,8 @@ class Customer
 end
 ```
 
-And write the query you need:
+### Writing Queries
+With your models set up, you can now write queries:
 
 ```ruby
   Invoice
@@ -79,6 +91,42 @@ And write the query you need:
     ).to_a
 ```
 
+### Standalone Mode
+You can also use `any_query` without models by creating a client directly:
+
+```ruby
+  sql_client = AnyQuery::Client.new(
+    adapter: :sql,
+    params: {
+      url: 'psql://user:password@localhost:5432/dbname',
+      primary_key: :id,
+      table: 'users'
+    }
+  )
+
+  csv_client = AnyQuery::Client.new(
+    adapter: :csv,
+    params: {
+      url: 'path/to/file.csv',
+      primary_key: :id,
+      fields: {
+        id: { type: :integer },
+        user_id: { type: :integer },
+        title: { type: :string },
+        body: { type: :string },
+        status: { type: :integer },
+        created_at: { type: :datetime, format: '%Y-%m-%d %H:%M:%S' }
+      }
+    }
+  )
+
+  # Querying
+  csv_client
+    .joins(sql_client, :user_id, :id, into: :user, strategy: :full_scan)
+    .select(:number, :date, :customerNumber, :netAmount)
+    .to_a
+```
+
 ## License
 
 The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).