make intermediate dirs in writeFile helper

src/utils/fs.js

@@ -1,10 +1,22 @@
 import Promise from 'es6-promise/lib/es6-promise/promise';
 import * as fs from 'fs';
-import { resolve } from './path';
+import { dirname } from './path';
+
+function mkdirpath ( path ) {
+	const dir = dirname( path );
+	try {
+		fs.readdirSync( dir );
+	} catch ( err ) {
+		mkdirpath( dir );
+		fs.mkdirSync( dir );
+	}
+}
 
 export function writeFile ( dest, data ) {
 	return new Promise( ( fulfil, reject ) => {
-		fs.writeFile( resolve( process.cwd(), dest ), data, err => {
+		mkdirpath( dest );
+
+		fs.writeFile( dest, data, err => {
 			if ( err ) {
 				reject( err );
 			} else {