fix logic in cabinet index which is resposible for ref link building

cabinet/views.py

@@ -16,7 +16,10 @@ class IndexView(ProtectedView):
     title = _('Личный кабинет')
 
     def get_ref_link(self,user):
-        return user.referral.url if user.referral else ""
+        return "{path}?ref={ref_link}".format(**{
+            'path': user.referral.url,
+            'ref_link': user.referral.code
+        })
 
     def get_bought_item_list(self,user):
         paginator = Paginator(object_list=user.buying_set.filter(status=BUYING_STATUS_IN_CART).order_by('create_at').all(), per_page=settings.DEFAULT_PAGE_AMMOUNT)