Allow admins to transfer cookbook ownership

:fork_and_knife: Implement the ability for Supermarket admins to transfer the ownership of a cookbook to any other user.
Yea it doesn't quite feel right to me either. I like your suggestion but it doesn't work for the case where an admin is trying to add a collaborator to their own cookbook, it will include collaborators that are already collaborating on the cookbook. It's more of a context problem then a authorization problem... looking for collaborators for transferring of ownership vs looking for collaborators for adding collaborators. I'd like to make this better but I'm unsure how to approach it. Anymore thoughts?