public/500.html
<!DOCTYPE html>
<html>
<head>
<title>We're sorry, but something went wrong (500)</title>
<link href="/static.css" media="screen" rel="stylesheet" type="text/css" />
</head>
<body>
<h1>500</h1>
<h3>We're sorry, but something went wrong.</h3>
<hr/>
<p>We've been notified about this issue and we'll take a look at it shortly.</p>
</body>
</html>