Update GettingStarted.vue

If you don't add `import 'vue-material/dist/theme/default.css'` for full bundling, things can go wrong on the page. You won't get your component color right.

Author: yingshaoxo

docs/app/pages/GettingStarted.vue

@@ -45,6 +45,7 @@
         import Vue from 'vue'
         import VueMaterial from 'vue-material'
         import 'vue-material/dist/vue-material.min.css'
+        import 'vue-material/dist/theme/default.css'
 
         Vue.use(VueMaterial)
       </code-example>