title: Object of type 'Product' is not JSON serializable
body: <p>I'm trying to pull the from my app via Django. The issue is when I call Order Detail via my serializers, I get this error:</p>
  
  <pre><code>TypeError at /api/customer/order/latest/
  Object of type 'Product' is not JSON serializable
  Request Method: GET
  Request URL:    http://localhost:8000/api/customer/order/latest/?access_token=XXXXXXXXXXXXXXXXXXXXXXXXXXXX
  Django Version: 1.10
  Exception Type: TypeError
  Exception Value:    
  Object of type 'Product' is not JSON serializable
  </code></pre>
  
  <p>I'm pulling the data from this Model:</p>
  
  <pre><code>class OrderDetail(models.Model):
      order = models.ForeignKey(Order, related_name='order_details')
      product_size = models.ForeignKey(ProductSize)
      quantity = models.IntegerField()
      sub_total = models.FloatField()
  
      def __str__(self):
          return str(self.id)
  
  # references Prodcut and allows old code to work.
      @property
      def product(self):
          return self.product_size.product
  </code></pre>
  
  <p>This is what is being pulled:</p>
  
  <pre><code>'order_details': [OrderedDict([('id', 68),
                                  ('product_size', 44),
                                  ('quantity', 1),
                                  ('sub_total', 20.0),
                                  ('product', &lt;Product: Bacon Burger - withDrink&gt;)])],
   'status': 'Your Order Is Being Picked Right Off The Plant!',
   'total': 20.0}
  request 
  &lt;WSGIRequest: GET '/api/customer/order/latest/?access_token=XXXXXXXXXXXXXXXXXXXXXXXXXXXX'&gt;
  </code></pre>
  
  <p>Serializers:</p>
  
  <pre><code>class OrderDetailSerializer(serializers.ModelSerializer):
  
      class Meta:
          model = OrderDetail
          fields = ("id", "product_size", "quantity", "sub_total", "product")
  
  
  class OrderSerializer(serializers.ModelSerializer):
      customer = OrderCustomerSerializer()
      driver = OrderDriverSerializer()
      restaurant = OrderRestaurantSerializer()
      order_details = OrderDetailSerializer(many = True)
      status = serializers.ReadOnlyField(source= "get_status_display")
  
      class Meta:
          model = Order
          fields = ("id", "customer", "restaurant", "driver", "order_details", "total", "status", "address")
  </code></pre>
  
  <p>Function for details:</p>
  
  <pre><code>def customer_get_latest_order(request):
      access_token = AccessToken.objects.get(token = request.GET.get("access_token"),
      expires__gt = timezone.now())
  
      customer = access_token.user.customer
      order = OrderSerializer(Order.objects.filter(customer = customer).last()).data
  
      return JsonResponse({"order": order})
  </code></pre>
  
  <p>I'm not sure what needs to be done.</p>