Just a friendly note to passers-by that GitLab, who originally forked 'grit' to 'gitlab-grit' in order to maintain it, has since switched to the 'rugged' gem.
https://twitter.com/gitlab/status/431428479469748225
https://github.com/gitlabhq/gitlab_git#moved-from-grit-to-rugged
mojombo#188 (comment)
And lastly, for your convenience:
https://rubygems.org/gems/rugged