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  Start Here

  Getting Started with Rails

  Models

  Active Record Basics

  Rails Database Migrations

  Active Record Validations

  Active Record Callbacks

  Active Record Associations

  Active Record Query Interface

  Views

  Layouts and Rendering in Rails

  Action View Form Helpers

  Controllers

  Action Controller Overview

  Rails Routing from the Outside In

  Digging Deeper

  Active Support Core Extensions

  Rails Internationalization API

  Securing Rails Applications

  Debugging Rails Applications

  Configuring Rails Applications

  Rails Command Line Tools and Rake Tasks

  Asset Pipeline

  Working with JavaScript in Rails

  Extending Rails

  Rails on Rack

  Creating and Customizing Rails Generators

  Contributing to Ruby on Rails

  Contributing to Ruby on Rails

  API Documentation Guidelines

  Ruby on Rails Guides Guidelines

  Release Notes

  Ruby on Rails 4.0 Release Notes

  Ruby on Rails 3.2 Release Notes

  Ruby on Rails 3.1 Release Notes

  Ruby on Rails 3.0 Release Notes

  Ruby on Rails 2.3 Release Notes

  Ruby on Rails 2.2 Release Notes

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Ruby on Rails 4.0 Release Notes

Highlights in Rails 4.0:

• Ruby 2.0 preferred; 1.9.3+ required
• Strong Parameters
• Turbolinks
• Russian Doll Caching

These release notes cover only the major changes. To know about various bug fixes and changes, please refer to the change logs or check out the list of commits in the main Rails repository on GitHub.