public function processMentions(Text $text)
{
// Turn @username into [@username](http://example.com/user/username)
$text->replace('/(?:^|[^a-zA-Z0-9.])@([A-Za-z0-9]+)/', function (Text $w, Text $username) {
$url = $this->config->site->url;
return ' [@' . $username . '](' . rtrim($url, '/') . '/user/0/' . $username . ')';
});
}