'Create a field on a model. Usually involves adding a column, but may
involve adding a table instead (for M2M fields).'

def add_field(self, model, field):

    if (field.many_to_many and field.remote_field.through._meta.auto_created):
        return self.create_model(field.remote_field.through)
    self._remake_table(model, create_field=field)
