Generate model and files for Relationships and follwing users
Add relationships table to database
Write test for checking validity of relationships between users
Write tests to check if user model recognizes relationships
Add association for user/relationships - user follower_id as foreign key
Write tests to check associations in relationships
Add associations to followed/follwer users
Fix error in test for relationship associations
Write tests to check validity of relationship if missing one half of relationship
Fix error in test
Add validations to ensure that follower/followed ids must be present
Write test for user recognizing its own followed users
Add has_many-through relationship for followed_users
Write tests for checking if user can follow another user
Add methods for checking the followed users and following users
Write tests for unfollowing users
Add unfollow method to destroy a relationship between two users
Fix error in follow! method
Fixed error in 'following' test
Write test for getting followers instead of followed users