use docker volume for data

docker-compose.yml

@@ -10,7 +10,7 @@ services:
       - /data/smb/adult/Games:/games/private:ro
       - /data/smb/media/Games/Computer:/games/public:ro
       # Persistent SQLite database
-      - ./data:/data
+      - game-grid-data:/data
     environment:
       NODE_ENV: production
       GAMES_PATH: /games
@@ -24,3 +24,5 @@ services:
       # Set to "true" only when the app sits behind an HTTPS reverse proxy
       SECURE_COOKIES: "false"
     restart: unless-stopped
+volumes:
+  game-grid-data: