feat: Send e-mail notifications to user

src/fellchensammlung/receivers.py

@@ -0,0 +1,17 @@
+from django.db.models.signals import post_save
+from django.dispatch import receiver
+from fellchensammlung.models import BaseNotification, CommentNotification
+from .tasks import task_send_notification_email
+
+
+@receiver(post_save, sender=CommentNotification)
+def comment_notification_receiver(sender, instance: BaseNotification, created: bool, **kwargs):
+    base_notification_receiver(sender, instance, created, **kwargs)
+
+
+@receiver(post_save, sender=BaseNotification)
+def base_notification_receiver(sender, instance: BaseNotification, created: bool, **kwargs):
+    if not created or not instance.user.email_notifications:
+        return
+    else:
+        task_send_notification_email.delay(instance.pk)