Add base and format code

web/index.html

@@ -11,6 +11,7 @@
             <div class="buttons">
                 <button value="0" v-on:click="click(0)">0</button>
                 <button value="1" v-on:click="click(1)">1</button>
+                <button value="2" v-on:click="click(2)">2</button>
             </div>
         </main>
         <script src="dist/app.js"></script>