Move game to nhl-game-builder

Create an idea of a game builder, apart from the game model itself, so
we can use mongo models for games.
Use mongoose game model as primary model

Instead of using a JSON object to represent an NHL game, use a mongo
object. Update the logic to create an nhl-game model and return that in
the schedule API
Create a "team" which has a "schedule"

Move things around so that we're importing a schedule which belongs to
a team. This means we must initially create a list of teams, which
still needs to be done -- for now just manually create one. Importing
commands exist for both schedule and teams.