cPanel 11 Stage 2 (currently in the most recent RELEASE build) have RoR functionality, including Rails and Gems options on cpanel.
Note: For RoR, Apache must have mod_proxy support.
How To Install Ruby on a cpanel Server
How TO Install And Setup Gems
Ruby Gems are collections of functions that allow you to perform tasks in Ruby. You will need to install a Gem before you can use it inside a Ruby program.
Note: Current cpanel version has some bugs or issue with Gem Setup. We may sometimes need to configure Gems and Rails from command line.