title: How to use regexp in routes with parameters?
body: <p>How to use regexp in routes with parameters?</p>
  <p>I want to set reg exp for asset parametr.</p>
  <p>For routes like this - <code>/opinions/a11</code></p>
  <pre><code>@Get([
        '/:category(opinions)/:asset([a-z0-9]{1,7})'
    ])
  </code></pre>
  <p>PS:
  It works, but how to limit length.
  <code>/:category(opinions)/:asset([a-z0-9]+)</code></p>