Dumpdata with unmanaged models

Dumpdata with unmanaged models

I'm trying to dump my database (sqlite3) to a json file for a fixture, but
I have an unmanaged model which is causing a no such table error
(obviously!) so how do you dumpdata with these kind of models in the db?
Model:
from django.db import models
class Backup(models.Model):
"""
This class is lazily recycled between various forms that ask the user to
provide a path to some data.
"""
dbloc = models.CharField(
max_length = 255
)
class Meta:
app_label = 'myApp'
db_table = 'backup'
managed = False
Error:
CommandError: Unable to serialize database: no such table: backup