Add Docker Compose quick reference guide

- Document common docker-compose commands
- Provide configuration examples
- Include troubleshooting section
- Add environment variables reference table
- Include production tips and best practices

DOCKER_COMPOSE.md

@@ -0,0 +1,158 @@
+# Docker Compose Quick Reference
+
+## Quick Start
+
+### Full Stack (Server + Agent)
+```bash
+docker-compose up
+```
+Access dashboard: http://localhost:8080
+Login: admin / admin
+
+### Server Only
+```bash
+docker-compose up server
+```
+
+### Agent Only
+```bash
+SERVER=your-server:8080 docker-compose up agent
+```
+
+## Common Commands
+
+```bash
+# Start services in background
+docker-compose up -d
+
+# Stop all services
+docker-compose down
+
+# View logs
+docker-compose logs -f
+
+# View logs for specific service
+docker-compose logs -f server
+docker-compose logs -f agent
+
+# Restart services
+docker-compose restart
+
+# Remove volumes/data
+docker-compose down -v
+
+# Rebuild images
+docker-compose build --no-cache
+```
+
+## Configuration
+
+### Change Server Credentials
+Edit `docker-compose.yml`:
+```yaml
+environment:
+  USERNAME: "myuser"
+  PASSWORD: "mysecurepassword"
+```
+
+### Change Agent Reporting Interval
+```yaml
+environment:
+  INTERVAL: "30s"  # Report every 30 seconds instead of 15
+```
+
+### Set Custom Agent ID
+```yaml
+environment:
+  AGENT_ID: "my-machine"
+```
+
+### Run Multiple Agents
+```bash
+# Terminal 1: Start server
+docker-compose up server
+
+# Terminal 2: Run agent 1
+docker-compose run --name agent1 -e AGENT_ID=machine1 agent
+
+# Terminal 3: Run agent 2
+docker-compose run --name agent2 -e AGENT_ID=machine2 agent
+```
+
+## Docker Commands
+
+### View Running Containers
+```bash
+docker-compose ps
+```
+
+### Execute Commands in Container
+```bash
+# Connect to server
+docker-compose exec server sh
+
+# View server config
+docker-compose exec server ps aux
+```
+
+### View Resource Usage
+```bash
+docker stats
+```
+
+## Troubleshooting
+
+### Agent can't connect to server
+```bash
+# Check if server is running and healthy
+docker-compose ps
+
+# Check server logs
+docker-compose logs server
+
+# Check if containers are on same network
+docker network inspect nerd-monitor
+```
+
+### Clear Everything and Start Fresh
+```bash
+docker-compose down -v
+docker-compose build --no-cache
+docker-compose up
+```
+
+### Port Already in Use
+If port 8080 is already in use, edit `docker-compose.yml`:
+```yaml
+ports:
+  - "8090:8080"  # Maps host port 8090 to container port 8080
+```
+
+## Environment Variables Reference
+
+### Server
+| Variable | Default | Description |
+|----------|---------|-------------|
+| ADDR | 0.0.0.0 | Bind address |
+| PORT | 8080 | Server port |
+| USERNAME | admin | Admin username |
+| PASSWORD | admin | Admin password |
+
+### Agent
+| Variable | Default | Description |
+| SERVER | server:8080 | Server address |
+| INTERVAL | 15s | Reporting interval |
+| AGENT_ID | (auto) | Agent identifier |
+
+## Production Tips
+
+1. **Change credentials**: Update USERNAME and PASSWORD in docker-compose.yml
+2. **Use external volumes**: Add volume mounts for data persistence
+3. **Set resource limits**: Uncomment resource limits in docker-compose.yml
+4. **Enable restart policies**: Already set to `unless-stopped`
+5. **Use environment files**: Create `.env` file for sensitive data:
+   ```bash
+   USERNAME=myuser
+   PASSWORD=mysecurepass
+   ```
+   Then in docker-compose.yml: `env_file: .env`