rails/README.md
schneems a3507b7674 [ci skip] CodeTriage badge
[Code Triage](https://www.codetriage.com/) is an app I've maintained for the past 4-5 years with the intent of getting people involved in open source. It sends subscribers a random open issue for them to help "triage". For Ruby projects such as "rails/rails" you can also subscribe to documentation. For example you can get a few random documented methods, or if you want to write docs, get undocumented methods.

The initial approach was inspired by seeing the work of the small core team spending countless hours asking "what rails version was this in" and "can you give us an example app". The idea is to outsource these small interactions to a huge team of volunteers and let the core team focus on their work.

The purpose of the badge is to give more people an easier way to start contributing to Rails. Here's what it currently looks like:

[![Code Triage Badge](https://www.codetriage.com/rails/rails/badges/users.svg)](https://www.codetriage.com/rails/rails)

The number is how many people are currently subscribed (a.k.a. "helpers") to the project on CodeTriage, the color is based off of the number of open issues in the project. You can see an example of this badge on another popular open source repo [Crystal](github.com/crystal-lang/crystal/).

> For context to non-rails core: I also maintain sprockets (though a release hasn't happened in some time, sorry), and I have commit to Rails. I'm not some rando trying to push arbitrary links to READMEs on GitHub.
2017-07-17 15:20:05 -05:00

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Welcome to Rails

Rails is a web-application framework that includes everything needed to create database-backed web applications according to the Model-View-Controller (MVC) pattern.

Understanding the MVC pattern is key to understanding Rails. MVC divides your application into three layers, each with a specific responsibility.

The Model layer represents your domain model (such as Account, Product, Person, Post, etc.) and encapsulates the business logic that is specific to your application. In Rails, database-backed model classes are derived from ActiveRecord::Base. Active Record allows you to present the data from database rows as objects and embellish these data objects with business logic methods. You can read more about Active Record in its README. Although most Rails models are backed by a database, models can also be ordinary Ruby classes, or Ruby classes that implement a set of interfaces as provided by the Active Model module. You can read more about Active Model in its README.

The Controller layer is responsible for handling incoming HTTP requests and providing a suitable response. Usually this means returning HTML, but Rails controllers can also generate XML, JSON, PDFs, mobile-specific views, and more. Controllers load and manipulate models, and render view templates in order to generate the appropriate HTTP response. In Rails, incoming requests are routed by Action Dispatch to an appropriate controller, and controller classes are derived from ActionController::Base. Action Dispatch and Action Controller are bundled together in Action Pack. You can read more about Action Pack in its README.

The View layer is composed of "templates" that are responsible for providing appropriate representations of your application's resources. Templates can come in a variety of formats, but most view templates are HTML with embedded Ruby code (ERB files). Views are typically rendered to generate a controller response, or to generate the body of an email. In Rails, View generation is handled by Action View. You can read more about Action View in its README.

Active Record, Active Model, Action Pack, and Action View can each be used independently outside Rails. In addition to that, Rails also comes with Action Mailer (README), a library to generate and send emails; Active Job (README), a framework for declaring jobs and making them run on a variety of queueing backends; Action Cable (README), a framework to integrate WebSockets with a Rails application; and Active Support (README), a collection of utility classes and standard library extensions that are useful for Rails, and may also be used independently outside Rails.

Getting Started

  1. Install Rails at the command prompt if you haven't yet:

     $ gem install rails
    
  2. At the command prompt, create a new Rails application:

     $ rails new myapp
    

    where "myapp" is the application name.

  3. Change directory to myapp and start the web server:

     $ cd myapp
     $ rails server
    

    Run with --help or -h for options.

  4. Using a browser, go to http://localhost:3000 and you'll see: "Yay! Youre on Rails!"

  5. Follow the guidelines to start developing your application. You may find the following resources handy:

Contributing

Code Triage Badge

We encourage you to contribute to Ruby on Rails! Please check out the Contributing to Ruby on Rails guide for guidelines about how to proceed. Join us!

Trying to report a possible security vulnerability in Rails? Please check out our security policy for guidelines about how to proceed.

Everyone interacting in Rails and its sub-projects' codebases, issue trackers, chat rooms, and mailing lists is expected to follow the Rails code of conduct.

Code Status

Build Status

License

Ruby on Rails is released under the MIT License.