📝 docs(README): add usage

Author: kazupon

README.md

@@ -6,10 +6,77 @@
 
 vue-i18n loader for custom blocks
 
-## :scroll: Changelog
-Details changes for each release are documented in the [CHANGELOG.md](https://github.com/kazupon/vue-i18n-loader/blob/dev/CHANGELOG.md).
+## :rocket: Usage
+
+the below `App.vue` have `i18n` custom block:
+```html
+<i18n>
+{
+  "en": {
+    "hello": "hello world!"
+  },
+  "ja": {
+    "hello": "こんにちは、世界!"
+  }
+}
+</i18n>
+
+<tempalte>
+  <p>{{ $t('hello') }}</p>
+</template>
+
+<script>
+export default {
+  name: 'app',
+  // ...
+}
+</script>
+```
+
+```javascript
+import Vue from 'vue'
+import VueI18n from 'vue-i18n'
+import App from './App.vue'
 
+Vue.use(Vue-i18n)
 
+const i18n = new VueI18n({
+  locale: 'en',
+  messages: {
+    en: {
+      // ...
+    },
+    ja: {
+      // ...
+    }
+  }
+})
+new Vue({
+  i18n,
+  render: h => h(App)
+}).$mount('#app')
+```
+
+configure webpack config for `vue-loader` (v11.3 later):
+
+```javascript
+module.exports = {
+  module: {
+    rules: [{
+      test: /\.vue$/,
+      loader: 'vue',
+      options: {
+        loaders: {
+          i18n: 'vue-i18n-loader'
+        }
+      }
+    }]
+  }
+}
+```
+
+## :scroll: Changelog
+Details changes for each release are documented in the [CHANGELOG.md](https://github.com/kazupon/vue-i18n-loader/blob/dev/CHANGELOG.md).
 
 ## :muscle: Contribution
 Please make sure to read the [Contributing Guide](https://github.com/kazupon/vue-i18n-loader/blob/dev/CONTRIBUTING.md) before making a pull request.