Bluebird Promise expected by loadGroups

[Morgul]

A Bluebird promise is expected to be return when you pass a function in to loadGroups, which means it does not work with async/await.

The current work around is to just pass in the results of calling your async function, since trivial perms calls Promise.resolve on anything that is passed in, and not a function, which both resolves async functions, and wraps it in the expected bluebird promise.

Frankly, we need to remove the bluebird dependency now that Promises are standard.

[Morgul]

This was fixed with 5adeb4b.