Merge branch 'Notification-bugfix' into 'master'

Error NoneType object - notification must first be saved

See merge request AlekSIS!239

aleksis/core/models.py

@@ -334,6 +334,7 @@ class Notification(ExtensibleModel):
         return str(self.title)
 
     def save(self, **kwargs):
+        super().save(**kwargs)
         if not self.sent:
             send_notification(self.pk, resend=True)
         self.sent = True