Open/Closed principle states "software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification"; that is, such an entity can allow its behaviour to be extended without modifying its code.

A class should only have a single responsibility, that is, only changes to one part of the software's specification should be able to affect the specification of the class.

Dragon Ruby is toolchain that allows developers the ability to build apps and games in Ruby.

The ViewComponent library will provide a new way for creating reusable and testable view components.

Thredded is a Rails 4.2+ forum/messageboard engine. Its goal is to be as simple and feature rich as possible.