Added .ruby-version files

* .ruby-version is a common format to specify the ruby version that a
  project should be used with (I set it to 2.0-p247 the most current
  official ruby release)
* This format is commonly accepted by ruby management tools
  (rvm, rbenv)
* the .ruby-gemset file is only used for RVM I believe
* what this does for me is when I go into that directory it
  automatically chooses the right ruby version and gemset (project
  specific gems) for me so it's really convenient
Merge pull request #5 from PragTob/ruby-version

Added .ruby-version files