'basic',
      'basePath' => dirname(__DIR__),
      'bootstrap' => ['log'],
      'components' => [
         'request' => [
            // !!! insert a secret key in the following (if it is empty) - this
               //is required by cookie validation
            'cookieValidationKey' => 'ymoaYrebZHa8gURuolioHGlK8fLXCKjO',
         ],
         'cache' => [
            'class' => 'yii\caching\FileCache',
         ],
         'user' => [
            'identityClass' => 'app\models\User',
            'enableAutoLogin' => true,
         ],
         //other components...
         'db' => require(__DIR__ . '/db.php'),
      ],
      'modules' => [
         'hello' => [
            'class' => 'app\modules\hello\Hello',
         ],
      ],
      'params' => $params,
   ];
   if (YII_ENV_DEV) {
      // configuration adjustments for 'dev' environment
      $config['bootstrap'][] = 'debug';
      $config['modules']['debug'] = [
         'class' => 'yii\debug\Module',
      ];
      $config['bootstrap'][] = 'gii';
      $config['modules']['gii'] = [
         'class' => 'yii\gii\Module',
      ];
   }
   return $config;
?>

 [
            'id' => '100',
            'username' => 'admin',
            'password' => 'admin',
            'authKey' => 'test100key',
            'accessToken' => '100-token',
         ],
         '101' => [
            'id' => '101',
            'username' => 'demo',
            'password' => 'demo',
            'authKey' => 'test101key',
            'accessToken' => '101-token',
         ],
      ];
      /**
      * @inheritdoc
      */
      public static function findIdentity($id) {
         return isset(self::$users[$id]) ? new static(self::$users[$id]) : null;
      }
      /**
      * @inheritdoc
      */
      public static function findIdentityByAccessToken($token, $type = null) {
         foreach (self::$users as $user) {
            if ($user['accessToken'] === $token) {
               return new static($user);
            }
         }
         return null;
      }
      /**
      * Finds user by username
      *
      * @param string $username
      * @return static|null
      */
      public static function findByUsername($username) {
         foreach (self::$users as $user) {
            if (strcasecmp($user['username'], $username) === 0) {
               return new static($user);
            }
         }
         return null;
      }
      /**
      * @inheritdoc
      */
      public function getId() {
         return $this->id;
      }
      /**
      * @inheritdoc
      */
      public function getAuthKey() {
         return $this->authKey;
      }
      /**
      * @inheritdoc
      */
      public function validateAuthKey($authKey) {
         return $this->authKey === $authKey;
      }
      /**
      * Validates password 
      *
      * @param string $password password to validate
      * @return boolean if password provided is valid for current user
      */
      public function validatePassword($password) {
         return $this->password === $password;
      }
   }
?>

public function actionAuth(){
   // the current user identity. Null if the user is not authenticated.
   $identity = Yii::$app->user->identity;
   var_dump($identity);
   // the ID of the current user. Null if the user not authenticated.
   $id = Yii::$app->user->id;
   var_dump($id);
   // whether the current user is a guest (not authenticated)
   $isGuest = Yii::$app->user->isGuest;
   var_dump($isGuest);
}

public function actionAuth() {
   // whether the current user is a guest (not authenticated)
   var_dump(Yii::$app->user->isGuest);
   // find a user identity with the specified username.
   // note that you may want to check the password if needed
   $identity = User::findByUsername("admin");
   // logs in the user
   Yii::$app->user->login($identity);
   // whether the current user is a guest (not authenticated)
   var_dump(Yii::$app->user->isGuest);
   Yii::$app->user->logout();
   // whether the current user is a guest (not authenticated)
   var_dump(Yii::$app->user->isGuest);
}