fix: add allauth to middleware

when the demo is run using
`python manage.py migrate --settings=demo.settings --noinput`
a `django.core.exceptions.ImproperlyConfigured` exception is thrown

demo/demo/settings.py

@@ -47,6 +47,7 @@
 )
 
 MIDDLEWARE = (
+    'allauth.account.middleware.AccountMiddleware',
     'corsheaders.middleware.CorsMiddleware',
     'django.contrib.sessions.middleware.SessionMiddleware',
     'django.middleware.common.CommonMiddleware',