title: Keep an existing, legacy git repo in sync with a new copy
body: <p>What's the best way to keep an existing git repo in sync with a git remote that will become the mainly used remote?</p>
  
  <p>My plan was to keep the TFS git code in sync with the primary VSTS git repo (as some people will only be able to access VSTS going forward) and we want to keep builds running from TFS. Unfortunately our TFS cannot receive inbound traffic for security reasons, therefore I was thinking that there would be a scheduled build in TFS that would fetch the latest from the VSTS repo and merge those changes in to the TFS repo (and therefore kicking off the CI builds as currently).</p>
  
  <p>I'm a bit lost in the various options (like mirroring and the like) - what approach would work best (or at least work!!)</p>