def delete(options = {:hard => false})
      if options[:hard]
        self.class.delete(self.id, options)
      else
        return if new_record? or destroyed?
        update_column kakurenbo_column, current_time_from_proper_timezone
      end
    end
def delete(options = {:hard => false})
      if options[:hard]
        self.class.delete(self.id, options)
      else
        return if new_record? or destroyed?
        update_column kakurenbo_column, current_time_from_proper_timezone
      end
    end
delete record.

 @param options [Hash] options.
 @option options [Boolean] hard (false) if hard-delete.