Authentication and DB changes.

[ppeters0502]

This PR implements the following:

• After having some major problems with postgres running locally on one machine versus another, we moved to using a simpler SQLite database, making the dev process a little cleaner as far as persisting data.
• Basic authentication with register, login and logout pages to support user roles in the future
• Basic auth-checks so that users cannot access the game page (http://localhost:8000/game/host or http://localhost:8000/game/join) without being authenticated. This might be extended in the future to include roles so that users who don't have game hosting permissions can't access "...game/host", but for right now this is just authentication checks.

For User Stories/Issues, this PR closes #15, #18, #8 and #9