Integrate ActiveJob / DeliverLater / GlobalID with Rails

WIP.
@tenderlove as the wrapper is a `Delegator` we cannot because delegator overrides `==` and compares the wrapped object (so `@mail==@mail.message` will be `true`). What we can assert is that the class of the wrapper is different from the class of the wrapped object: `assert_not_equal @mail.class, @mail.message.class`. Works for you?