This hook is executed every time somebody uses
git push to push commits to the repository. It always resides in the remote repository that is the destination of the push and not in the originating (local) repository.
The hook runs before any references are updated. It is typically used to enforce any kind of development policy.
The script takes no parameters, but each ref that is being pushed is passed to the script on a separate line on standard input in the following format:
<old-value> <new-value> <ref-name>