- OmniAuth (https://github.com/intridea/omniauth)
- Devise (https://github.com/plataformatec/devise) – Flexible authentication solution for Rails with Warden.
- Cancan(https://github.com/ryanb/cancan) – CanCan is an authorization library for Ruby on Rails which restricts what resources a given user is allowed to access. All permissions are defined in a single location (the Ability class) and not duplicated across controllers, views, and database queries.
- Haml (http://haml.info) – Haml is a markup language that’s used to cleanly and simply describe the HTML of any web document without the use of inline code. Haml functions as a replacement for inline page templating systems such as PHP, ASP, and ERB, the templating language used in most Ruby on Rails applications. However, Haml avoids the need for explicitly coding HTML into the template, because it itself is a description of the HTML, with some code to generate dynamic content.
- Capybara(https://github.com/jnicklas/capybara) – Acceptance test framework for web applications