title: Yii 2 - using custom helpers
body: <p>I'm trying to use a custom helper class which i create under <code>frontend/components/Helper</code> (Helper.php)</p>
  
  <p>The content of that file is something like:</p>
  
  <pre><code>&lt;?php
  namespace frontend\components\Helper;
  
  class Helper {
  
      public static function helperGreetings() {
          echo("hello helper");
      }
  }
  ?&gt;
  </code></pre>
  
  <p>and on my SiteController.php i have the following:</p>
  
  <pre><code>use frontend\components\Helper;
  
  class SiteController extends Controller
  {
      public function actionIndex()
      {
          Helper::helperGreetings();
          return $this-&gt;render('index');
      }
  }
  </code></pre>
  
  <p>What should i do to have it working?</p>
  
  <p>BTW, the error i get is Unknown Class – yii\base\UnknownClassException</p>
  
  <pre><code>Unable to find 'frontend\components\Helper' in file: /Users/foo/sites/bar.dev/frontend/components/Helper.php. Namespace missing?
  </code></pre>