Recently, in a moment of well-timed stubbornness, I came across arel’s ability to merge scopes. Merging greatly expands the ways in which you can apply scopes, and so too the kinds of logic you can put in them. As far as I can see, though, they’re not very widely used. In fact, the only place I’ve seen them referred to is in this excellent railscast by Ryan Bates. Well, here’s my sell. For those n