Shopify was hiring in January, not sure what it's like now. I'd also love working on RoR projects, and have seriously enjoyed developing on Shopify.
I hated their CLI tool for app dev because I like tinkering myself, but I would've probably built the same thing in bash, so having a maintained CLI is nice.
Too bad I'm a medior, so there's a low chance they'd hire me ;P
There's also much more to Shopify than just Ruby feature work. I've heard tales of their infrastructure and it seems like it would be very exciting for the right kind of person.
Never worked there, probably never will, but they have my respect for the things I have seen, read and heard.