title: Dumpdata with unmanaged models
body: <p>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 <code>no such table</code> error (obviously!) so how do you dumpdata with these kind of models in the db?</p>
  
  <p>Model:</p>
  
  <pre><code>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
  </code></pre>
  
  <p>Error:</p>
  
  <p><code>CommandError: Unable to serialize database: no such table: backup</code></p>