Rails is a compilation of programming libraries used as a method for developing web applications. These are its major aspects:

Rails applies the MVC pattern for application design. – application code is divided into models, views and controllers.
Rails gives foundation classes from which the model and controller classes take over, giving them a whole bunch of capability without scripting a single line of code outside the class declaration.
Rails contains Active Record(AR) module that makes available an ORM that instantiates Ruby objects from database tables automatically.
Rails has a lot of classes and methods to make possible common tasks in web applications.