/**
* Get list of users mentioned in given text.
*/
protected function findMentionedUsers(string $text) : Collection
{
preg_match_all('/@([a-z0-9_-]+)/i', $text, $matches, PREG_SET_ORDER);
$nicknames = array_pluck($matches, 1);
return User::whereIn('name', $nicknames)->get();
}