Stats CRUD + Unit Tests

@johnhof Here is the stats model + CRUD

Take aways:
  I moved the mongoose functions to static methods on the model
    -- CON: This bloats the model
    -- PRO: Now the core functionality is accessible from the object rather than a route

We can really think of models as a "Class"

May cause Merge conflicts with #28 (though I believe I mitigated them)