If you're going to get involved in Ruby/Rails development, you really don't want the distribution's repositories to control your version(s) of Ruby, nor the gems you install. You also don't want the overhead of building from tarballs yourself. Check out the Ruby Version Manager, rvm, at
http://rvm.beginrescueend.com/. It allows you to have multiple Rubies installed side-by-side and has some more advanced options for managing separate gemsets or configuring specialized configurations like REE, Ruby Enterprise Edition.