def add?(record)
      result = @set.add?( formatted_name( record ) )
      return result if result
      flag(record)
      result
    end
def add?(record)
      result = @set.add?( formatted_name( record ) )
      return result if result
      flag(record)
      result
    end
Add record to set.  Flag if covered already.
 @param record [Object] ActiveRecord object instance
 @return [Object, nil] Object if added safely, nil otherwise