Taken from PR 199779 with minor modifications.
Proposed commit message:
new port: security/omniauth-gitlab Ruby gem that implements the OmniAuth strategy of GitLab for usage in rubygem-onmiauth. WWW: https://github.com/linchus/omniauth-gitlab PR: 199779 Submitted by: Torsten Zuehlsdorff <ports@toco-domains.de> Approved by: swills (mentor), mat (mentor)