public function register()
{
$user = new Users();
$user->username = $this->username;
$user->email = $this->email;
$user->password = $this->password;
$user->first_name = $this->first_name;
$user->last_name = $this->last_name;
$user->last_login = time();
$user->avatar = UploadedFile::getInstance($this, 'avatar');
$user->save();
return Yii::$app->user->login($user, 3600 * 24 * 7);
}
