title: NelmioApiDocBundle doesn't work "No operations defined in spec!"
body: <p>I want to use nelmio for symfony-project, but it doesn't work.</p>
  
  <p>It always says: No operations defined in spec!</p>
  
  <p>I also try the example on <a href="https://symfony.com/doc/current/bundles/NelmioApiDocBundle/index.html" rel="nofollow noreferrer">https://symfony.com/doc/current/bundles/NelmioApiDocBundle/index.html</a></p>
  
  <p>Whats's wrong? Any ideas?</p>
  
  <p>routing.yml</p>
  
  <pre><code>app.swagger_ui:
      path: /api/doc
      methods: GET
      defaults: { _controller: nelmio_api_doc.controller.swagger_ui }
  </code></pre>
  
  <p>config.yml</p>
  
  <pre><code>nelmio_api_doc:
      areas:
          path_patterns: # an array of regexps
          - ^/api(?!/doc$)
          host_patterns:
          - ^api\.
  </code></pre>
  
  <p>Controller</p>
  
  <pre><code>/**
   * @Route("/api/test", methods={"GET"})
   * @SWG\Response(
   *     response=200,
   *     description="Returns the rewards of an user"
   * )
   * @SWG\Parameter(
   *     name="order",
   *     in="query",
   *     type="string",
   *     description="The field used to order rewards"
   * )
   */
  public function testAction()
  {
  
  }   
  </code></pre>
  
  <p>composer.json</p>
  
  <pre><code>"symfony/symfony": "3.4.*",
  "nelmio/api-doc-bundle": "3.2.1",
  </code></pre>