docs: docker-compose.example.yml for end-user deploy

docker-compose.example.yml

@@ -0,0 +1,32 @@
+# Example deployment of package-updater itself.
+# Copy to /home/shcizo/self-hosted/package-updater/docker-compose.yml
+# and create a .env file alongside containing:
+#   UPDATER_API_KEY=<openssl rand -hex 32>
+
+services:
+  package-updater:
+    image: registry.example.com/package-updater:latest
+    container_name: package-updater
+    restart: unless-stopped
+    environment:
+      - UPDATER_API_KEY=${UPDATER_API_KEY}
+      - STACKS_ROOT=/home/shcizo/self-hosted
+      - LOG_LEVEL=info
+      - PORT=8080
+      - UPDATE_TIMEOUT=5m
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock
+      - /home/shcizo/self-hosted:/home/shcizo/self-hosted:ro
+    labels:
+      - "se.shcizo.auto-update=true"
+    networks:
+      - proxy
+    healthcheck:
+      test: ["CMD", "wget", "-q", "-O-", "http://localhost:8080/healthz"]
+      interval: 30s
+      timeout: 5s
+      retries: 3
+
+networks:
+  proxy:
+    external: true