Added purchaseGames method
Merge commit '15c5fa22e9fb7b3c9fc00585659ea76d1863365c' into db-pre-fill
Added utils API for creating a promise map (takes a map of keys to promises, returns a map of keys to results)
Hooked up users and games creation (run concurrently and join when done), and call purchaseGames when done
Merge commit '69f97283a340259819736fe84f50f36b0bb0a04f' into db-pre-fill