Add relationship model, add following/follower associations (has many and has many through)
Add following/follwed stats to profile view and root page, implement follow/unfollow button to profile view unless current_user?(@user) as well as appropriate tests to respec
Add following/follow actions in users_controller, implement views for those actions, write tests to check authorization for non-signed users trying to request following_user_path(followers_user_path as well as tests for signed-in users
Add working follow/unfollow button as well as tests for checking the buttons
Add Ajax request toform in follow/unfollow partial, implement tests to check proper response to Ajax requests to Relationships#create/Relationships#destroy, create create.js.erb as well as destroy.js.erb to respond to accepted formats in request header
Include js files in application.rb for precompiling on heroku
Implement feed for microposts of users followed by current_user as well as his own microposts -> Micropost.from_users_followed_by(user) (using subselects for effecient lookup), add tests to check newsfeed
Change file permission