增加一个连接到课程主页

dashboard/src/pages/demo/course/index.tsx

@@ -9,6 +9,8 @@ export default ({}: IProps) => {
     <div>
       <h1>List items page</h1>
       <Link to="/demo">Go home</Link>
+      &nbsp;
+      <Link to="/demo/course">课程主页</Link>
     </div>
   );
 }