add_includes

# File activerecord/lib/active_record/serializers/xml_serializer.rb, line 189
    def add_includes
      procs = options.delete(:procs)
      @serializable.send(:serializable_add_includes, options) do |association, records, opts|
        add_associations(association, records, opts)
      end
      options[:procs] = procs
    end