title: Routes error with django models migrations
body: <p>I have a file named routes.py where I have that </p>
  
  <pre><code>router.register('orders', OrderViewSet, 'order')
  </code></pre>
  
  <p>If I comment that I don't have problems with the migrations, but in production, and my boss say I cannot comment that every time that I want to migrate.</p>
  
  <p>In te serializer.py I have this:</p>
  
  <pre><code>class OrderSerializer(serializers.ModelSerializer):
      buyer_obj = serializers.SerializerMethodField()
      #items = ProductSerializer(many=True, read_only=True)
      class Meta:
          model = Order
          fields = ('id', 'url', 'buyer', 'items', 'store', 'buyer_obj',
              'browser_ip', 'currency', 'enabled',
              'financial_status', 'gateway', 'total_amount')
  </code></pre>
  
  <p>The Error is the next:</p>
  
  <pre><code>django.db.utils.OperationalError: (1054), "Unkown column 'orders_order.currency' in 'field list'")
  </code></pre>
  
  <p>Please exist another form to migrate that?
  Thank you.</p>