Github as primary source of backend mono repo

Hi all mono repo users.

To speed up development and code refactoring towards multi-repo, I proposed to switch our primary source repository to Github. This means that our git operations (pull, push, clone, and fetch) will be done towards Github, while code review will still be resided in Phabricator.

Please note that the improvement on Github monorepo should not block the current commitment to work on multi repo. (The use of Github monorepo will be reviewed at the end of Q3 2019).

If you think that your team workflow will be impacted by the initiatives, please join to discuss the impact analysis here.

Impact summary:

Herald job that based on commit or branch push will no longer work

If you use this hook to trigger build please see the workaround

Pull request might be supported, however team must ensure that the change doesn't break develop
Expect development freeze during the switch (1 to 2 hours)

If by 3rd April of 2019 nobody have other concern, we will immediately conduct the initiatives. The transition steps will be posted separately.

Thanks.