THIS COMMAND is for reviewing applications made to tilde.town. it's for admins to run.

signups land in `/town/signups` as JSON files. This tool iterates over them and
lets an admin take one of a few actions:

- skip
- approve
- reject
- notate (leave a note for other admins)
- jump to random signup

some other requirements in no particular order:

- JSON files should be locked when being looked at
- notation modifies the JSON in place
- approved signups go to `/town/signups/approved`
- rejected signups go to `/town/signups/rejected`

I'm not 100% sure yet what approval is going to look like; I want to switch to
a system where people are emailed about their acceptance and given a code they
can exchange for an ssh form that lets them pick a username and add a pubkey.

so for now i'm just going to move the files into `/town/signups/approved` while
i think about that.