changed step names

step1-04/src/App.tsx

@@ -0,0 +1,13 @@
+import React from 'react';
+
+
+export class App extends React.Component {
+  render() {
+
+    return (
+        <div>
+         
+        </div>
+    );
+  }
+}

step1-04/src/index.tsx

@@ -0,0 +1,4 @@
+import React from "react";
+import ReactDOM from "react-dom";
+import { App } from "./App";
+ReactDOM.render(<App />, document.getElementById("app"));