Add postgres

[natedunn2230]

• Postgres spins up for dev and test environments
• Data is persistent for dev mode, resets for tests
• Reformatted entrypoint for the application and added cli utility
• Added placeholder model for user to verify db works

Making this PR now so you can look at it. I'll update once #23 is merged, since i'll need to tidy up a few things for the linter.

[natedunn2230]

I'll fix the test workflow once I get your changes. I'll maybe rethink my changes for that