Adds a scheduled task to remove old notification entries from the database

InvenTree/common/tasks.py

@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+import logging
+from datetime import timedelta, datetime
+
+from django.core.exceptions import AppRegistryNotReady
+
+
+logger = logging.getLogger('inventree')
+
+
+def delete_old_notifications():
+    """
+    Remove old notifications from the database.
+
+    Anything older than ~3 months is removed
+    """
+
+    try:
+        from common.models import NotificationEntry
+    except AppRegistryNotReady:
+        logger.info("Could not perform 'delete_old_notifications' - App registry not ready")
+        return
+
+    before = datetime.now() - timedelta(days=90)
+
+    # Delete notification records before the specified date
+    NotificationEntry.objects.filter(updated__lte=before).delete()