GitLab is a GitHub like git-repository manager, and more. It supports “repository management”, issue tracking, wiki, groups, and even LDAP authentication . Git is managed by gitolite .
Sometimes creating/moving repositores goes wrong and repositories are no longer available for push/pull or are not moved in gitolite (e.g. the ui shows the new location, SSH the old or both). As of 4.2 GitLab brings some helpers for this.
Also check the help page in the GitLab installation.