Adding a SQLite DB to properly track the keys is going to take a while. For
now I'll just keep them in the config file and give them 30-day expirations.
The new method is much nicer and doesn't require the manual make-old-git
step. The top-level command is actually build_and_minimize.bash, which uses
`git archive` to unpack the last Git commit and build with _that_ Dockerfile
and Docker context. This is better for determinism. It's similar to our build
process for that one big project at work.
Trisha