Welcome!
Ruby on Rails on IBM i? Tell me it is so!
 
Ah! Indeed it is!
Currently you are experiencing, directly, a Rails application running on IBM i. This is an implementation of the Radiant CMS that you can find Radiant here. There isn't too much "magic" going on. The server is running IBM i version 6.1 and the *only* modifications needed, at least at this point, was to use the JRuby implementation of Ruby so I could use JDBC for the database connection thus avoid the additional expense of DB2 Connect to connect to the DB2 for i database engine.
Waddaya think?