What is Ruby on Rails?
Ruby on Rails, often shortened to Rails or RoR, is an open source web application framework for the Ruby programming language.

Install multiple Rails applications per cPanel account
You can create multiple rails applications and choose production or development environments. Rails applications can also be set to be rebooted if for any reason the server is restarted. You can also install your own custom gems via the cPanel interface. (cPanel uses Apache to rewrite requests to your rails application.)