Add FRIEND_STATUSES and replaced FOLLOWER_SYMBOLS with RELATIONSHIP_SYMBOLS
update ImagrUser.friends() to account for new FRIEND_STATUSES
Update ImagrUser.end_friendship() to set friendship between users to 0
Update ImagrUser.end_friendship() to clean and save
Update relationships added via following methods to include 0 entries for friendship
Add ImagrUser.request_friendship() to submit a friend request
Update settings.py to use postgres instead of sqllite