fix: use correct CREATE_SUPERUSER env var for bugsink

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: fey

docker-compose.override.yml

@@ -20,5 +20,4 @@ services:
     environment:
       - SECRET_KEY=localdev-hexlet-devops-example-app-not-for-production-use
       - ALLOWED_HOSTS=localhost,bugsink
-      - SUPERUSER_EMAIL=admin@example.com
-      - SUPERUSER_PASSWORD=admin
+      - CREATE_SUPERUSER=admin@example.com:admin