title: Sylius No css and images, nothing in /web/assets directory
body: <p>i just installed Sylius, all seems to be ok but when i launch <code>app_dev.php</code>, I have no css and JS.</p>
  
  <p>I checked <code>/web/assets/</code> : directory is empty</p>
  
  <p>Can you help me? </p>
  
  <p>Thank you</p>