Keep Tails' devel branch synced with the stable branch

This is only about Tails' Git repo.

Whenever we merge something, like a bugfix, into stable, we are then supposed to merge stable into devel to keep them synced. I frequently forget this, but it seems like something that could be automated. The only case I expect this to not be straightforward for is when there are merge conflicts. In that case, I suppose whoever pushed to stable triggering the merge should be notified about the conflict, and that it has to be resolved manually.

Is this possible?