Add relationship model and its database migration.
Establish the association between users and relationships.
Continue establishing the association between users and relationship
models: followed users, follow, unfollow and following?.
Tests for the above.
Finish establishing the association between users and relationships:
followers.
Refactor sample_data.rake and add method to populate relationships
table.
Add following followers stats to user home page and user profile page.
Add follow and unfollow forms.
Add routes for following, followers and relationships.
Fix some typos in sample_data.rake.
Tests.
Add following and followers actions to users controller.
Add view for following and followers actions.
Add tests for the above.
Add relationships controller with create and destroy actions.
Tests for creation and destruction of relationships through follow and
unfollow buttons.
Follow/unfollow users with Ajax and tests for it.
Add microposts by followed users to the user feed.
Tests for it.