Is there an easy way of putting up a scaffold-like multiple-select for the has_and_belongs_to_many relationship? I''d really like this sort of thing for all of those relations, since I seem to be doing it frequently, but I can see that it''s not quite a scaffold action, since it reads from the model. I could also just memorize (or keep) the code I keep re-using. But is there some other, easier, way?