I have been using Grails for some time now, but in school they are making us use Ruby on Rails. I have been trying to find an extension for ruby on rails for STS as there is for Grails, but I have failed. The only thing that comes close is a plugin so i can use ruby code in my Grails app using JRuby. I just want to make sure that a fully integrated extension DOESN'T exist.

If that is the case, what would be the graphical IDE way of developing in ruby on rails, the same way one would use STS for Groovy on Grails development? (preferably free :) )