Remove unused code and update readme

src/index.tsx

@@ -1,17 +1,10 @@
 import React from 'react';
 import ReactDOM from 'react-dom';
-import './index.css';
-import App from './App';
-import * as serviceWorker from './serviceWorker';
+import App from './components/App';
 
 ReactDOM.render(
-  <React.StrictMode>
-    <App />
-  </React.StrictMode>,
-  document.getElementById('root')
+	<React.StrictMode>
+		<App />
+	</React.StrictMode>,
+	document.getElementById('root'),
 );
-
-// If you want your app to work offline and load faster, you can change
-// unregister() to register() below. Note this comes with some pitfalls.
-// Learn more about service workers: https://bit.ly/CRA-PWA
-serviceWorker.unregister();