[JRO] the Forwardable module + Rails 4.2. No good

From: https://github.com/cequel/cequel/issues/193

> So it sounds like ActiveSupport 4.2 introduces an incompatible
> definition of instance_delegate that clobbers the same method as defined
> in Forwardable; is that correct? If so, this seems like a regression in
> ActiveSupport—Forwardable is, after all, part of the standard library,
> so Rails shouldn't make it impossible to use it.

Subclassing Module and using the delegate class method will effectively
get around this.