Display has_piece on the webpage

Change-Id: I81ff1c7a821e55c35207613f0045582f5ecb6175
diff --git a/y2019/vision/server/www/index.html b/y2019/vision/server/www/index.html
index c970ce1..dc06ed6 100644
--- a/y2019/vision/server/www/index.html
+++ b/y2019/vision/server/www/index.html
@@ -63,6 +63,14 @@
           <div id="stilts" class="dof">
           </div>
         </div>
+
+        <div class="dof_container">
+          <div class="dof_name">
+            has_piece
+          </div>
+          <div id="has_piece" class="dof">
+          </div>
+        </div>
       </div>
     </div>
   </body>