title: How to enable source maps in create-react-app?
body: <p>everyone.</p>
  
  <p>I am a new member of react and I created my app use <code>create-reat-app</code> .I used <code>node-sass-chokidar</code> package like <a href="https://github.com/facebookincubator/create-react-app/blob/master/packages/react-scripts/template/README.md#adding-a-css-preprocessor-sass-less-etc" rel="noreferrer">react's document</a>. But I don't know how to enable "source maps" of scss file.</p>
  
  <p>Thanks for any help.</p>