code: def create_db_entry(self, comment=''):
          
          jbfile = JB_File(self)
          p = jbfile.get_fullpath()
          user = dj.get_current_user()
          tf = dj.models.TaskFile(path=p, task=self.task, version=self.version,
                                         releasetype=self.releasetype, descriptor=self.descriptor,
                                         typ=self.typ, user=user)
          tf.full_clean()
          tf.save()
          note = None
          if comment:
              try:
                  note = dj.models.Note(user=user, parent=tf, content=comment)
                  note.full_clean()
                  note.save()
              except Exception, e:
                  tf.delete()
                  raise e
          return tf, note
docs: Create a db entry for this task file info
          and link it with a optional comment
  
          :param comment: a comment for the task file entry
          :type comment: str
          :returns: The created TaskFile django instance and the comment. If the comment was empty, None is returned instead
          :rtype: tuple of :class:`dj.models.TaskFile` and :class:`dj.models.Note`
          :raises: ValidationError, If the comment could not be created, the TaskFile is deleted and the Exception is propagated.