title: django oscar commerce: Conflicting 'stockrecord' models in application
body: <p>I am using oscarcommerce for my django project. I want to extend the "StockRecord" model to include some more fields. So I forked the partner app as follows. (boscar is my app name)</p>
  
  <pre><code>python manage.py oscar_fork_app partner boscar/ 
  </code></pre>
  
  <p>It successfully forked and new files were added to boscar/partner folder. I added 'boscar.partner' in my installed apps.</p>
  
  <p>Now I added new fields in StockRecord models as follows</p>
  
  <p>boscar/partner/models.py</p>
  
  <pre><code>from django.db import models
  from oscar.apps.partner.abstract_models import AbstractStockRecord
  
  
  class StockRecord(AbstractStockRecord):
      effective_price = models.FloatField(default=0, null=True)
      is_instock_item = models.BooleanField(default=False, null=True)
      instock_quantity = models.IntegerField()
  
  from oscar.apps.partner.models import *  # noqa
  </code></pre>
  
  <p>Now when I try to make migrations it shows the following error.</p>
  
  <pre><code>RuntimeError: Conflicting 'stockrecord' models in application 'partner': &lt;class 'oscar.apps.partner.models.StockRecord'&gt; and &lt;class 'boscar.partner.models.StockRecord'&gt;.
  </code></pre>
  
  <p>I already successfully forked the catalogue and order models and that are working fine. Only this "StockRecord" models showing this error.</p>