Show php errors in browser

We are working in a web application with PHP, i’m starting with Sentry and by the moment the notifications works very well but the developers can’t see the errors in screen (environment is development), always we have to check the dashboard, our configuration is like this:

$ravenClient = new Raven_Client($dsn);
  $ravenClient->tags_context(array('TipoError' => 'PHP Error', 'Instance'=>_INSTANCE_NAME));

What i have to do to show errors in screen and my dashborad.
Thank you for your help :smiley: