Adapt some details for django 2.0 upgrade

django_backend/backend/frontend/views.py

@@ -29,9 +29,10 @@ def _api_error_response():
 # Response for StateView, LogoutView, and all post requests
 def _api_state_response(request):
     response = {
-        'logged_in': request.user.is_authenticated()
+        'logged_in': request.user.is_authenticated
+
     }
-    if request.user.is_authenticated():
+    if request.user.is_authenticated:
         response['user'] = serializers.UserSerializer(request.user).data
 
 

django_backend/backend/models.py

@@ -318,9 +318,12 @@ class SSHPublicKey(models.Model):
         max_length=1000
     )
     # hidden field at the user
+    # TODO checks: if the user is null
     user = models.ForeignKey(
         User,
         related_name='_ssh_keys',
+        on_delete=models.SET_NULL,
+        null=True,
     )
 
     # has the user triggered the deletion of this key