GitLab/Mirroring projects

Preparations

 * Create a target repo on GitHub, if you haven't already. This can be done by importing the gitlab.wikimedia.org repo.
 * Create a personal access token in GitHub. This is done on https://github.com/settings/tokens?type=beta. Add permission "Contents" -> "Access: Read and write".

Set up push mirror

 * 1) In the repo view in gitlab.wikimedia.org go to "Settings" (bottom in the left hand menu) -> "Repository".
 * 2) Expand "Mirroring repositories".
 * 3) Enter the HTTPS URL of the GitHub repo, same as the clone URL, but include username, i.e. https://username@github.com/....git.
 * 4) Leave "Mirror direction", it seems you can't change it anyway.
 * 5) Select "Password" for "Authentication method".
 * 6) In "Password" enter the personal access token from your GitHub account.
 * 7) Click "Mirror repository". You should get a message at the top of the page saying it worked.

Test configuration

 * 1) Make a commit in the Gitlab repo.
 * 2) Click the circular arrows ("Update now") to start an update. If it goes through changes should be pushed to the GitHub repo.