add_includes

# File activerecord/lib/active_record/serialization.rb, line 46
      def add_includes(&block)
        if include_associations = options.delete(:include)
          base_only_or_except = { :except => options[:except],
                                  :only => options[:only] }

          include_has_options = include_associations.is_a?(Hash)
          associations = include_has_options ? include_associations.keys : Array(include_associations)

          for association in associations
            records = case @record.class.reflect_on_association(association).macro
            when :has_many, :has_and_belongs_to_many
              @record.send(association).to_a
            when :has_one, :belongs_to
              @record.send(association)
            end

            unless records.nil?
              association_options = include_has_options ? include_associations[association] : base_only_or_except
              opts = options.merge(association_options)
              yield(association, records, opts)
            end
          end

          options[:include] = include_associations
        end
      end