I'm going to assume this:
http://artoo.io/documentation/platforms/spark/
Okay, I've stared at it for a bit, and although I don't know ANY Ruby, I'm not sure why it wouldn't work. It just makes calls to the Tinker firmware, which also runs on a Photon (provided you haven't flashed your own firmware over it!) Could you confirm whether or not Tinker is running on your Photon by trying the mobile app, or checking this page to see if the Tinker functionalities are showing up?
You could try editing the URL to the currently more accurate api.particle, rather than api.spark, but that really shouldn't make a difference.
Have a look at this as well, might just be what you're looking for 