Use Ruby 1.8 syntax for the Gemfile, and add a required Ruby version.
This will make it easier for people to understand when they have a ruby version problem while trying to run bundle install.
If you run bundle install with ruby 1.8, you get this confusing error:
12:46 ~/git/gitlabhq (master)$ bundle install
Gemfile syntax error:
/Users/aaronstone/git/gitlabhq/Gemfile:14: syntax error, unexpected ':', expecting $end
gem "mysql2", group: :mysql
^
After this PR, you will get a very readable error message:
12:48 ~/git/gitlabhq (master)$ bundle install
Your Ruby version is 1.8.7, but your Gemfile specified 1.9.3