RFC: Scheduled daily task for specific repos to know show how different staging / prod is

[orta]

Proposal:

Once a day, ideally in the morning, Peril runs a job that shows how many commits are in staging but are not deployed to master.

Reasoning

Metaphysics staging today is 9 days different from production, it would have been nice to keep track of that difference over time rather than when someone noticed that a bug wasn't fixed.

As we should be using the same naming conventions everywhere it's a matter of looking at the diff between master and production (or something like that)

This would be set up as a map, so artsy/metaphysics => #graphql, artsy/gravity => #frontend-notifications.

Exceptions:

Opt-in, so no exceptions.

[orta]

We've built this once: https://github.com/joeyAghion/releasecop