11.1.1  add relationship model
11.1.2  specify user/relationship model associations
11.1.3  presence validations for relationship model
11.1.4  add functionality for following and unfollowing users
11.1.5  implement followers functionality to users
11.2.1  update rake populate data task to include followers
11.2.2  relationship stats and follow/unfollow form
11.2.3  following and followers pages
11.2.4  contoller functionality for follow/unfollow button
11.2.5  using Ajax for follow & unfollow form button
11.3.1  tests and user model update for multiuser feed
11.3.2  first feed implementation
11.3.3  use a subselect query in creating the feed