[Rapzid]

I second Pry. It's amazing how fast you can use AR to add a little add-hoc business logic on-top of a DB and then drop a console with Pry to get a sort of custom interactive command line DSL :)

TBH if I was writing anything large enough for this kind of stuff to get out of hand, I would seriously consider a statically typed language like Golang or C#/F#(which both have absolutely fantastic tooling). REPL's don't help the next person to come along figure out what your methods are taking in and what those calls return. But I digress.

I don't always cut Ruby, but when I do I cut it with Pry... Yeah.