Redhat support

In short:

- Add Gluster Epel recipe
- tested with CentOS 6.5, using Vagrant and Rackspace Cloud
- grabbed Gemfile, Rakefile, .rubocop.yml from https://github.com/AutomationSupport/templatestack and put them in this repo, for consistency with the latest *rules*
- Rubocop and Foodcritic are happy with this release

~Simone
I found this approach quite *modular*.
Say that we want to enable/disable GlusterFS repo in favour of Epel one, we can simply put a *switch case* there.
Please, feel free to give me suggestions ;)