Added basic login.

src/argv.js

@@ -0,0 +1,11 @@
+import yargs from 'yargs';
+
+const { argv } = yargs()
+	.command('npm start')
+	.option('debug', {
+		describe: 'Show error stack traces',
+		type: 'boolean',
+		default: process.env.NODE_ENV === 'development',
+	});
+
+export default argv;