Mutual Relationships with Rails

I'm following episode 163 of railscasts and it enables user to signify another user is there friend, but that's more or less it.

I would like to have a helper that finds if a user is their friend.

Get a list of users who are friends of each other.

List of users that have been sent re开发者_StackOverflow社区quests that aren't mutual.

@friends_out = Friendship.where(:user_id=>current_user.id) #users "i" want to be friends with
@friends_in = Friendship.where(:friend_id=>current_user.id) #users who want to be friend with "me"
# users who haven't added "my" id to Friendship and vice versa
# user who are my friend and i'm their friends.

How do I do that?

Thanks.

---

class User < ActiveRecord::Base
  def friends_with?(user)
    self.friendships.where(:friend_id => user.id).any?
  end

  def friends_with_me?(user)
    user.friendships.where(:friend_id => self.id).any?
  end

  def mutual_friends?(user)
    friends_with?(user) && friends_with_me?(user)
  end
end

Then you could do something like:

current_user.friends_with?(other_user)