The script was creating a group named 'dispatch' (hardcoded) while
nginx.conf expected a group matching POSTGRES_USER (e.g., 'dispatcharr').
Changes:
- Use $POSTGRES_USER for group name instead of hardcoded 'dispatch'
- Make sed command more robust to match any existing user directive
This ensures the group name matches the user name, fixing the error:
"getgrnam("dispatcharr") failed in /etc/nginx/nginx.conf:1"
Fixes#877
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>