Add sqlite3 CLI

[mrkurt]

This adds the sqlite3 CLI to the build, and generates a shortcut for connecting to the database. It will work in any Docker environment.

To connect to sqlite in a running Docker container, run docker exec -ti <container> database-cli.

On Fly.io, you can run fly ssh console -C database-cli.

[kentcdodds]

Sounds cool! Mind making this change to the Blues Stack as well?

[mrkurt]

We're looking at the blues stack! It's a little harder, and we have fly pg connect -a <db-name> for this reason. I think we may be able to make fly pg connect work by default from the app directory. I'll add instructions at least.

[mrkurt]

@kentcdodds one other thing: I moved the env vars from fly.toml into the Dockerfile. This makes the Dockerfile more useful outside the Fly.io environment. It also made it easier to test this change. :)

[kentcdodds]

Cool! Thanks for these improvements 👏