/**
* Check if an username exists in the database (used in forgotten password)
*
* @param string $username user username
* @param string $role user role (optional)
* @param int $exclude - exclude a user
* @return string|false
*/
public function nameExists($username = '', $role = '', $exclude = 0)
{
require_once LIBS . 'UserInfo.php';
$userInfo = new UserInfo();
return $userInfo->nameExists($this, $username, $role, $exclude);
}