I'm glad you love using GitLab to manage your automation projects. Luckily, you can still use the Omnibus install but change the default usernames :) In `/etc/gitlab/gitlab.rb` we have the following configuration options:

registry['username'] = "registry" registry['group'] = "registry" user['username'] = "git" user['group'] = "git" postgresql['username'] = "gitlab-psql" redis['username'] = "gitlab-redis" web_server['username'] = 'gitlab-www' web_server['group'] = 'gitlab-www' mattermost['username'] = 'mattermost' mattermost['group'] = 'mattermost'

Change these to acceptable values and it should work well for you. If there are any other blockers in the Omnibus package, please create an issue at https://gitlab.com/gitlab-org/omnibus-gitlab/issues and we'll do our best to accommodate them.