GitLab is customized using GitLab's admin interface. Some options can ony be
gitlab.yml. For such situations, use the Web terminal's
and create a file named
/app/data/gitlab.yml. This way custom configurations
will be preserved across updates and will also be backed up.
By default, GitLab allows external people to sign up. This can be disabled to restrict use only to Cloudron users as follows:
GitLab > Admin area > Settings > Features > remove the check mark "Sign-up enabled"