GitLab CEO here, as you mention backing up the git repository is very important. We just announced free hosting for git-annex files and repositories on GitLab.c

GitLab CEO here, as you mention backing up the git repository is very important. We just announced free hosting for git-annex files and repositories on GitLab.com that might be good for your use case, see https://about.gitlab.com/2015/02/17/gitlab-annex-solves-the-problem-of-versioning-large-binaries-with-git/ https://about.gitlab.com/2015/02/17/gitlab-annex-solves-the-... for an overview.