Update the guide for the ruby 2.0 upgrade.
Provide rvm install instructions and a link to http://rvm.io/rvm/install

Provide example for development version of rvm.
Epel is optional.

Pass the url to the epel-release-6-8.noarch.rpm directly to yum.
Update link to fedoraproject instead of a mirror.
Merge pull request #174 from jrafanie/update_guide_for_ruby_2

Update the guide for the ruby 2.0 upgrade.