Define initial filesystem structure

[jboxman]

I've used something similar to this with some success.

- .gitignore
- .env : secrets, not committed, for local testing, actually ignored by heroku
- package.json
- app.js : bootstrap server, for heroku
- client/
-- [variety of client files]
- server/
-- app.js : actual entry point for testing
-- models/
--- index.js : initializes the actual mongodb connection
-- views/
-- routes/