archive/app/models/archive_category.rb

class ArchiveCategory
  include Mongoid::Document
  field :category_id, type: String
  field :sort_number, type: Integer
  after_initialize do |record|
	if(!record.new_record? && record.sort_number.class != Fixnum)
		record.sort_number = 0
		record.save
    elsif(!record.new_record?)
		@category = Category.find(record.category_id) rescue nil
		if !@category.nil?
			@sort_number = @category.sort_number rescue nil
			if !@sort_number.nil?
				record.sort_number = @sort_number
				record.save
			end
		else
			record.destroy
		end
	end
  end
  after_save do |record|
	@category = Category.find(record.category_id) rescue nil
	if !@category.nil?
		@sort_number = record.sort_number rescue nil
		if !@sort_number.nil?
			if !@category.attributes[:sort_number].nil?
				@category.sort_number = @sort_number
				@category.save
			end
		end
	end
  end
end