django.contrib.sites.models RuntimeError:模型类。Site没有声明显式的app_label，也不在INSTALLED_APPS中的应用程序中

I am building an application with Django Rest Framework and AngularJs. I am using Django-rest-auth for my authentication purposes, although, I have not been able to set it up. Anyway, I am trying to set up this I am building an application with Django Rest F