Remove app.js dummy code

src/app.js

@@ -1,3 +0,0 @@
-module.exports = () => {
-	return 'Hello World!';
-}

test/test.js

@@ -1,8 +0,0 @@
-const assert = require('chai').assert;
-const app = require('../src/app');
-
-describe('App', () => {
-	it('should greet with Hello World!', () => {
-		assert.equal(app(), 'Hello World!');
-	});
-});