init

helloworld/src/App.js

@@ -0,0 +1,13 @@
+import React, { Component } from 'react';
+import logo from './logo.svg';
+import './App.css';
+import HelloWorld from './HelloWorld';
+class App extends Component {
+  render() {
+    return (
+      <HelloWorld message="Hello React!" />
+    );
+  }
+}
+
+export default App;