Made createUser call asynchronous as well.
Refactored tests to make them async. Added test for creating tournament with insufficient privileges.
Check MongoDB connection when initializing storage.js
Added GET /tournaments service + basic test.
Added GET /users to retrieve list of users + simple test.
Refactoring serviceWrapper.js
Refactored storage.js
Simplified tests and serviceWrapper.js. Removed redundant test-checks covered by other tests.