added relationship attribute test
added test to ensure relationship assignment
add presence validation to relationships
add followed_users relationship to user model
add follow? and follow! action to user
added unfollow action to user model
added reverse_relationship virtual table
updated task for generating relationships
added routes for follers and following pages
added stats, follow, and unfollow partials
test pass
added ajax
added from_user_followed_by method to micropost model