Shipping Basecamp 2.0 for iOS
37svn.com
37svn.com
I contest that this is not great advice for other people interested in learning to program for iOS, maybe for Nick it's applicable (I believe him) but in general, just learn Objective C followed by Swift.
I think they'll be missing out when people download for a single device and miss out on the app on their second device.
That said, they basically tell version 1 was RubyMotion, version 2 is ObjC and version 3 will be Swift, just for the sake of learning...