Add buddies

https://trello.com/c/bjJNY4Ub/44-users-can-friend-each-other

Some latent code was commented for next PR
user_id_one and user_id_two are user IDs that will but user to find the appropriate buddy relationship.  Since this method is unaware who the buddy requester is and who the buddy requestee is, they kind of exist in parity.  I agree that there could be a better name, but as it is, these two ids exist kind of in a schroedinger juxtaposition