add search function

app/templates/boxes/show.html

@@ -8,6 +8,7 @@
     </div>
     <div class="actions">
         <a href="/boxes">返回箱子列表</a>
+        <a href="/search">去搜索</a>
         <a class="button" href="/boxes/{{ box.id }}/items/new">添加物品</a>
     </div>
 </div>