🐛(docker-compose) run node container as logged-in user

Running the container as root will install npm modules with root
access rights and generate issues when running the application with
the logged in user as we do it with Docker Compose.

docker-compose.yml

@@ -142,6 +142,7 @@ services:
       - ".:/app"
 
   y-webrtc-signaling:
+    user: ${DOCKER_USER:-1000}
     build: 
       context: .
       dockerfile: ./src/frontend/Dockerfile