This is only a partial solution, right?
Services such as Backhub.co also backup your issues:
https://backhub.co/features/backup-github-issues/
(we have 1000+ closed issues in our project, nice to preserve)
Right. The service is certainly expected to do more. Was mostly addressing the issue of mirroring the data to dropbox. But even then my "solution" only saves whatever you do locally. So if you merge PRs through github, it wouldn't get mirrored.
https://git-scm.com/docs/git-remote#git-remote-emset-urlem
and you are about done.