For starters, you need to pass both user ids to your controller, something like:
<%= link_to 'Add as a friend', :controller => 'users', :action =>'friendify', :id=>@current_user, :friend_id=>some_other_user.id %>
You should then be able to add the friend to the collection directly:
def friendify @user = User.find(params[:id]) @new_friend = User.find(params[:friend_id]) @user.friends << @new_friend end
Cheers, Max
