Docker Compose WAF: Add SafeLine to Any Existing Stack in 3 Steps

The Situation

You already have a Docker Compose stack running: Nginx + your app + PostgreSQL + Redis. It works. You don't want to rebuild it. But you want WAF protection in front.

Here's how to add SafeLine to an existing Docker Compose project without disrupting anything.

Step 1: Create a Shared Network

# docker-compose.yml (add to your existing file)