Change mongo connection variable name
Remove localhost override from server.js
Update user model to store most recent game ID
Add new route to use the new gameId value on user objects
Update route to use most recent games for users
Remove localhost as override
Handle cases where users do not have a most recent game
Merge pull request #256 from gjtrowbridge/switch-to-most-recent-game-id

feature(many): Change database, switch user's most recent game storage method