Ruby on Rails 4.2
Fedora 22 includes Ruby on Rails 4.2, the latest version of the well-known web application framework written in Ruby. Highlights in this release include Active Job, asynchronous mails, Adequate Record, Web Console and foreign key support. The upstream release notes are at http://guides.rubyonrails.org/4_2_release_notes.html
Information for developers upgrading existing applications to Ruby on Rails 4.2 can be found in the Upgrading Ruby on Rails guide at http://guides.rubyonrails.org/upgrading_ruby_on_rails.html