Update docs nav.

docs/_includes/nav/main.html

@@ -28,8 +28,8 @@
                     <a href="http://issues.wenzhixin.net.cn/bootstrap-table/" target="_blank">Examples</a>
                 </li>
                 <li>
-                    <a href="http://bootstrap-group-select.wenzhixin.net.cn" target="_blank">
-                        Bootstrap Group Select
+                    <a href="https://github.com/wenzhixin/bootstrap-table-fixed-columns" target="_blank">
+                        Fixed Columns
                         <span class="badge">New</span>
                     </a>
                 </li>