Update example docker-compose for webrcade

examples/docker-compose.example.yml

@@ -7,6 +7,7 @@ services:
     container_name: romm
     environment:
       - ROMM_DB_DRIVER=mariadb # mariadb | sqlite (default: sqlite)
+      - ROMM_HOST=https://localhost:3000 # your host ip or domain name (including http(s)://, subdomain and port if needed)
       # [Optional] Only required if using MariaDB as the database
       - DB_HOST=romm_db
       - DB_PORT=3306