title: Symfony 3 - Assetic dump works on dev but doesn't work on prod
body: <p>I'm new with symfony 3 and I'm trying to develop a web app application. To combine my css and js files, I've installed assetic bundle and I'm using it on dev mode, It works fine and I haven’t any problems.</p>
  
  <p>Then when I try to test my web app on production mode, css and js are not complete and the website doesn't work fine.</p>
  
  <p>I’ve tried these two commands but nothing has changed:</p>
  
  <ul>
  <li><code>php bin/console assetic:dump -env=prod</code></li>
  <li><code>php bin/console cache:clear --no-warmup -e prod</code></li>
  </ul>
  
  <p>The only way to make production work is to set <code>$kernel = new AppKernel('prod', true);</code> on app.php file, but I don't think this is the best solution.</p>
  
  <p>Any ideas?</p>
  
  <p>Here my code on base template:</p>
  
  <pre><code>{% block stylesheets %}
          {% stylesheets
          'css/dist/bootstrap.css'
          'css/dist/bootstrap-grid.css'
          'css/dist/bootstrap-reboot.css'
          'css/dist/font-awesome.css'
          'css/dist/sidenav.css'
          'css/dist/head.css'
          'css/dist/main.css'
          filter='cssrewrite' output='css/compiled/app.css' %}
          &lt;link rel="stylesheet" href="{{ asset_url }}"&gt;
          {% endstylesheets %}
      {% endblock %}
  </code></pre>
  
  <p>As you can see I get my css files from <code>&lt;root&gt;/web/css/dist/*</code> and I dump on <code>&lt;root&gt;/web/css/compiled/app.css</code> the file is created on dump, But not all css are there.</p>
  
  <p>Same procedure for js files.</p>