Improve auth folder.

web/src/auth/Util.js

@@ -0,0 +1,27 @@
+// Copyright 2021 The casbin Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import {message} from "antd";
+
+export function goToLink(link) {
+  window.location.href = link;
+}
+
+export function showMessage(type, text) {
+  if (type === "success") {
+    message.success(text);
+  } else if (type === "error") {
+    message.error(text);
+  }
+}