Reordering children using Sortable with nested_set / Awesome nested_set, and similar

sorting_nested_set_children.rb

  def reorder_children(ordered_ids)
    ordered_ids = ordered_ids.map(&:to_i)
    current_ids = children.map(&:id)
    unless current_ids - ordered_ids == [] && ordered_ids - current_ids == []
      raise ArgumentError, "Not ordering the same ids that I have as children. My children: #{current_ids.join(", ")}. Your list: #{ordered_ids.join(", ")}. Difference: #{(current_ids - ordered_ids).join(', ')} / #{(ordered_ids - current_ids).join(', ')}" 
    end
    j = 0
    transaction do
      for new_id in ordered_ids
        old_id = current_ids[j]
        if new_id == old_id
          j += 1
        else
          Category.find(new_id).move_to_left_of(old_id)
          current_ids.delete(new_id)
        end
      end
    end
  end

Found this on StackOverflow ... what would order_ids be? I am hoping just an array of IDs