use appError on socket io

backend/src/libs/socket.ts

@@ -1,5 +1,6 @@
 import socketIo, { Server as SocketIO } from "socket.io";
 import { Server } from "http";
+import AppError from "../errors/AppError";
 
 let io: SocketIO;
 
@@ -9,7 +10,7 @@ export const initIO = (httpServer: Server): SocketIO => {
 };
 export const getIO = (): SocketIO => {
   if (!io) {
-    throw new Error("Socket IO not initialized");
+    throw new AppError("Socket IO not initialized");
   }
   return io;
 };