Do not hardcode server name in Javascript files

display/main.js

@@ -132,7 +132,7 @@ document.addEventListener("mousemove", (e) => {
 });
 
 document.addEventListener("DOMContentLoaded", () => {
-    let webSocket = new WebSocket("ws://localhost:8081/socket");
+    let webSocket = new WebSocket("/socket");
     webSocket.addEventListener("message", (e) => {
         let nudgeReq = JSON.parse(e.data);
         n.nudge(nudgeReq[0] / 10, nudgeReq[1] / 10);