created a hierarchical structure of components

frontend/src/components/App/App.test.js

@@ -1,6 +1,6 @@
 import React from 'react';
 import ReactDOM from 'react-dom';
-import App from './App';
+import App from './index';
 
 it('renders without crashing', () => {
   const div = document.createElement('div');

frontend/src/components/App/Dummy/dummy.test.js

@@ -1,5 +1,5 @@
 import React from 'react';
-import Dummy from '../Dummy';
+import Dummy from './index';
 import renderer from 'react-test-renderer';
 
 test('Dummy renders correctly', () => {

frontend/src/components/App/index.js

@@ -1,7 +1,7 @@
 import React, { Component } from 'react';
-import logo from './logo.svg';
-import styles from './App.css';
-import Dummy from './components/Dummy';
+import logo from '../../logo.svg';
+import styles from './styles.scss';
+import Dummy from './Dummy';
 
 class App extends Component {
   render() {

frontend/src/index.js

@@ -1,7 +1,7 @@
 import React from 'react';
 import ReactDOM from 'react-dom';
 import './index.css';
-import App from './App';
+import App from './components/App';
 import registerServiceWorker from './registerServiceWorker';
 
 ReactDOM.render(<App />, document.getElementById('root'));