updated urls

Author: Zobeir-Rigi

chat-app/backend/app.js

@@ -58,7 +58,7 @@ const server = http.createServer(app);
 
 const PORT = process.env.PORT || 3000;
 
-server.listen(PORT, "0.0.0.0", () => {
+server.listen(PORT, () => {
     console.log("server is running");
 });