Storybook (#122)

* adding storybook

* update webpack config

* Update package.json

* udpating build script

stories/index.stories.js

@@ -0,0 +1,6 @@
+import React from 'react'
+import { storiesOf } from '@storybook/react'
+import Widget from '../src/components/widget'
+
+storiesOf(`Widget`)
+  .add(`default`, () => <Widget />)