title: Add existing gitlab project to a group/subgroup
body: <p>I have a gitlab group with some subgroups within in it. I would like to transfer repositories that were created independently to a subgroup of mine. Is there a way to do this, with all the members, history, commits, etc that are currently in the projects. I can simply create a new project in the subgroup and transfer the files there, but we will lose the history, etc.</p>
  <p>Thank you in advance!</p>