Completely re-write logic to prevent "hacking"

[rfree18]

All logic currently occurs on the client, making it super easy for someone to manually manipulate their buddy's attributes. This should be moved to a custom backend that verifies all actions and prevents hacking.

Things to do:

1. Build framework for backend, based on expressjs and Mongoose
2. Implement authentication based on passportjs
3. Re-implement save feature to work with new Mongoose instance
4. Re-implement all game logic to occur on the backend (at least as much as possible)
5. Deploy to AWS

[rfree18]

Things completed:

1. Complete
2. Complete
3. In Progress
4. To Do
5. In Progress