'Add (save to db) the passed in metadata.
Usage:
question = Question.objects.get(pk=1)
question.add_metadata(ff_version=\'3.6.3\', os=\'Linux\')'

def add_metadata(self, **kwargs):

    for (key, value) in kwargs.items():
        QuestionMetaData.objects.create(question=self, name=key, value=value)
    self._metadata = None
