title: Chartist: remove all grid lines but display axis
body: <p>I know there is an option to remove gridlines: <code>showGrid: false</code>. But that will remove all grid lines including main axes.</p>
  <p><strong>Is there a way to remove all gridlines except main axis like this?</strong>
  <a href="https://i.stack.imgur.com/SUnBy.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SUnBy.png" alt="enter image description here" /></a></p>