fixes bug to search page search

@@ -4,6 +4,7 @@
             <form id="search-form" action="{{url}}" method="get">
                 <i class="search-icon iconfont">&#xe60f;</i>
                 <input type="text" value="{{default}}" name="query">
+                <input type="hidden" value="search" name="search">
                 <i class="clear-input iconfont hide">&#xe61a;</i>
                 <button id="search" class="search" type="submit">搜索</button>
             </form>