Export room list as json file

server/server.js

@@ -239,3 +239,12 @@ try {
   console.error("Could not start to listen on port", PORT);
   throw error;
 }
+
+setInterval(async () => {
+  const fileContent = JSON.stringify(generateRoomList());
+  await fs.promises.writeFile(
+    path.join(__dirname, "rooms.json"),
+    fileContent,
+    "utf8"
+  );
+}, 2000);