Track deployments

[rsyring]

Since we deploy from a local dev machine, there is no obvious way to tell what the last deploy was and/or if the code you have currently has been deployed. We could build in some functionality that:

• Log deploys to a text file that gets commited
• Or, maybe it would be better to store in a shared AWS store of some kind
  • In this case, give a command mu deploys list mu deploys status or similar to show deploys for an app and/or environment
• Track if dirty (i.e. uncommited) deployment
• Track GH commit hash deployed if not dirty
• Add some sanity checking. E.g. can't deploy to production unless code is committed and pushed