Relationships

1) add view RelationshipsController specs
2) add Relationship model, specs
3) add validation on relationship to be unique
4) add user socializes spec - following, unfollowing

Please, approve.
Oh duh. I'm sorry. I looked at the `source: :followed` in the `has_many :followings` line and went with that line. The opposite would be `relationships.count`, so that should work.