What’s the easiest way to integrate Cloudinary with my Rails app?

We have a Ruby GEM for simple integration with RoR.

We recommend using CarrierWave together with Cloudinary’s plugin for managing images in your Rails application. For more details, see this general screen-cast about CarrierWave and our following blog posts for details about the integration process itself.
Attachinary is also a great option for managing attachments in your Rails application, see details here.
For accessing transformed images from your Rails view, you can use our cl_image_tag method: http://cloudinary.com/documentation/rails_integration#display_and_transform