Add Gemfile.lock to repo and modify .gitignore.

Gemfile.lock will prevent bundle having to recompile all the
dependencies each time. It is suggested to keep this in the repository
unless writing a Gem.

http://stackoverflow.com/questions/4151495/should-gemfile-lock-be-included-in-gitignore
Merge branch 'master' of https://github.com/bradysullivan/HackRails