chore: update .gitignore to include .env.example and enhance deployment documentation with Caddy reverse proxy setup

DEPLOYMENT.md

@@ -82,3 +82,35 @@ docker ps
 ```
 
 Look for the "healthy" status in the STATUS column.
+
+## Caddy Reverse Proxy (Optional - Production)
+
+For production deployments with automatic SSL/TLS certificates, Caddy can be used as a reverse proxy. Caddy provides:
+
+- Automatic Let's Encrypt certificates (including wildcard certificates)
+- HTTP to HTTPS redirect
+- Optimized settings for audio streaming and file uploads
+- Support for both `hoerdle.de` and `hördle.de` (Punycode: `xn--hrdle-jua.de`)
+
+### Quick Start
+
+1. **Follow the setup guide**: See `CADDY_SETUP.md` for detailed instructions
+2. **Configure environment variables**: Add GoDaddy API credentials to your `.env` file
+3. **Start with Caddy**:
+   ```bash
+   docker compose -f docker-compose.yml -f docker-compose.caddy.yml --profile production up -d
+   ```
+
+### Without Caddy
+
+If you don't want to use Caddy, you can deploy normally:
+
+```bash
+docker compose -f docker-compose.yml up -d
+```
+
+The application will still be accessible on port 3010, but you'll need to configure SSL/TLS separately (e.g., with nginx).
+
+### Caddy Troubleshooting
+
+See `CADDY_SETUP.md` for detailed troubleshooting information.