add under construction message

public/client.html

@@ -168,6 +168,7 @@
       <div id="modal-content" class="modal-content">
          <div class = "eztunesDrumKeyboard" id="eztunesDrumKeyboard"> </div>
          <button type="button" class="close" data-dismiss="modal">&times;</button>
+         <div> Under Construction! </div>
       </div>
     </div>