* add qq group description in document home page.

docs/index.json

@@ -230,6 +230,9 @@
                 "topics": [{
                     "name": "官方QQ群：384135104",
                     "url": null
+                }, {
+                    "name": "加群暗号：ZUI is sexy",
+                    "url": null
                 }]
             }, {
                 "id": "forum",

index.html

@@ -51,7 +51,7 @@
               <a href="#basic/download" class="btn btn-white btn-lg">快速上手 <i class="icon icon-hand-right"></i></a>
               <p><small>最新版本 <span class="zui-version"><i class='icon icon-spin icon-spinner-indicator'></i></span> &nbsp; <a style="color: #f1f1f1" href="https://github.com/easysoft/zui/archive/master.zip" target="_blank">下载源码</a></small></p>
             </div>
-            <p>QQ群：384135104 &nbsp; <a href="http://forum.zui.sexy/forum/" style="color: #f1f1f1" target="_blank"><i class="icon icon-comments-alt"></i> 论坛</a></p>
+            <p><span data-toggle="tooltip" data-html="true" title="加群请注明加群缘由，<br>或者使用暗号：ZUI is sexy">QQ群：384135104</span> &nbsp; <a href="http://forum.zui.sexy/forum/" style="color: #f1f1f1" target="_blank"><i class="icon icon-comments-alt"></i> 论坛</a></p>
           </div>
           <div id="search">
             <div id="searchForm">