title: Django two models share a table, run the unit test, then syncdb will report exception:table already exists
body: <pre><code>class A(models.Model):
      name = models.CharField(max_length=100)
      class Meta:
          db_table = "some_table"
  
  class B(models.Model):
      title = models.CharField(max_length=100, db_column="name")
      class Meta:
          db_table = "some_table"
  </code></pre>
  
  <p>we get two models sharing a table, and we create the database schema manually via a customized command named <code>./manage.py db</code>.
  but for unit test, when running <code>./manage.py test</code>, 
  an error occurs: <code>"Table 'some_table' already exists"</code>.</p>
  
  <p>how to avoid running <code>./manage.py syncdb</code> and execute the manual command?</p>