Add error when game code is empty

src/views/Home.vue

@@ -31,7 +31,7 @@
       The game has started, lets go!
     </template>
 
-    <HelloWorld msg="Welcome to Your Vue.js + TypeScript App"/>
+    <HelloWorld msg="Welcome to Your Vue.js + TypeScript App" />
   </div>
 </template>
 
@@ -77,6 +77,10 @@ export default class Home extends Vue {
   }
 
   private joinGame() {
+    if (this.code === '') {
+      this.error = "Game code cannot be empty when joining a game";
+      return;
+    }
     PerudoApi.instance.joinGame(this.name, this.code).then((response: JoinCreateGameObject) => {
       this.playerId = response.player.id;