Add Down Command

[ssickles]

This is WIP.

I started adding a down command but need to clarify whether we really want to allow someone to destroy an app or db via a single command. If someone is using this to automate putting an app to "sleep" while it isn't being used they might want an auto-approve mechanism of some kind. Anyway, too many questions and not the top priority so I created this PR and we can come back to it later.