`RedisMultiQueue ` inherits from `Base` and overloads class method `all`, changing the method signature. 

Choosing to return only a hash feels like an unnecessary gotcha because it's different from both previous versions of Resque and other single-queue implementations - ie your `Redis` class has the same method, but it returns an array. It would be nice if Redis and RedisMultiQueue had the same basic API, as far as possible.

You could extend RedisMultiQueue to provide the additional functionality - ie implement an `.all_by_queue` method.