lib/popular/popular.rb
def befriend new_friend
      run_callbacks :befriend do
        friendships.create friend_id: new_friend.id, friend_type: new_friend.class.name
      end
    end
def befriend new_friend
      run_callbacks :befriend do
        friendships.create friend_id: new_friend.id, friend_type: new_friend.class.name
      end
    end
Adds a friend to an instance's friend's list

 @param [Object] new_friend a popular_model that the instance is not already friends with

 @example
   user = User.create name: "Justin"
   other_user = User.create name: "Jenny"
   user.befriend other_user

   user.friends_with? other_user #=> true