Signup screen and functionality

frontend/lib/backend.dart

@@ -1,7 +1,8 @@
 
+import 'package:http/http.dart' as http;
 import 'dart:html';
 import 'dart:convert';
-import 'dart:async'; // Import for handling Completers
+import 'dart:async';
 
 class ChatInfo {
   int id;
@@ -31,6 +32,23 @@ class Backend {
     connect();
   }
 
+  static Future<void> signup(String username, String email, String password) async {
+    final response = await http.post(Uri.parse("$_url/user/signup"),
+      headers: {
+        'Content-Type': 'application/json',
+      },
+      body: jsonEncode({
+        'username': username,
+        'email': email,
+        'password': password,
+      })
+    );
+
+    if (response.statusCode < 200 || response.statusCode >= 300) {
+      throw Exception("Signup Status Code ${response.statusCode}");
+    }
+  }
+
   static Future<void> auth(String username, String password) {
     _socket!.send(json.encode({'username': username, 'password': password}));
     _credentials = (username: username, password: password);
@@ -43,7 +61,7 @@ class Backend {
   }
 
   static void connect() {
-    _socket = WebSocket(_url!);
+    _socket = WebSocket(_url! + "/ws");
     _socket!.onOpen.listen((event) {
       print('Connected to the WebSocket server');
       Backend.invalidateCache(chat: true);