MVC Architecture

Ruby on Rails is built around the model-view-controller(MVC) pattern. It simply means to separate the data, logic, and display layers of your program.

Models

These are basically classes in Ruby on Rails that talk to the database. These classes act as an interface between you and database. You need not to write SQL queries most of the time.

These are resources that you use in the application. For example: User, Post, Article, Idea etc.
They are usually accompanied by database layer. Most of the time you will have tables in the database accompanying your model. Like a User model will have users table etc.

Views

It handles the front-end of your application. It displays the output to browser and responding with non-html data. In a standard Rails application, views comprises of HTML, CSS, JavaScript, template engines etc. You will have to work with view files like for displaying list of users, you will have users.html.erb where .erb is an ERB template which contains HTML as well as Ruby statements.

Controllers

It takes user input (like a URL) and decides what to do (like show a page, post a comment, etc.) They are responsible for choosing the right model and sending data to the views. Also, as your Rails knowledge improves, with constant refactoring, you move business logic into the model (fat model, skinny controller). In most cases, controllers just take inputs, may process something useful, call model methods, and pass values to the view.

General Flow of Application

The General flow of a Rails application:

A request is made via a browser
The request is received at router of rails application
The request is routed to appropriate action in a controller
The specific action in controller either renders a view template or communicates with model
The model communicates with database
The model sends back information to controller
The controller renders view

File Naming Pattern

The following table will give an idea how the files in Model, View or Controller and table looks like in a standard Rails application and also notice the naming pattern (or convention, rather).

Models	Views	Controllers	Table Name
`User`	`home.html.erb`	`users_controller.rb`	`users`
`Post`	`new.html.erb`	`posts_controller.rb`	`posts`
`Article`	`article.html.erb`	`articles_controller.rb`	`articles`