This package still uses ruby 2.1. Ruby 2.1 is no longer supported upstream and will be removed soon. Please update your package to use a newer ruby slot. Use ruby 2.2 if you can only use one slot and your package is in arch Use ruby 2.3 if you can only use one slot and your package is in ~arch Use as many ruby targets as possible when you can use multiple slots.
Hans do you mind taking care of this? Not that I particularly dislike Ruby but you seem the best fit for the mission. Ping me if you need help.
I've added the ruby22 and ruby23 targets.