title: Symfony 3, include a css library with some dependencies
body: <p>From a personal symfony 3 project, I want use the font-awesome library. In the config.yml file I added an asset like that : </p>
  
  <pre><code>    awesomefont_css:
          inputs:
              - '%kernel.root_dir%/../web/library/font-awesome/css/font-awesome.css'
  </code></pre>
  
  <p>I call the asset from my index.php page : </p>
  
  <pre><code>{% stylesheets output="stylesheet.css"
  '@bootstrap_css'
  '@awesomefont_css'
  "@style_css"
  %}
  &lt;link rel="stylesheet" href="{{ asset_url }}"/&gt;
  {% endstylesheets %}
  </code></pre>
  
  <p>I cleared caches (via php bin/console cache:clear) but when I load my php page, I get the errors : </p>
  
  <p><a href="https://i.stack.imgur.com/3DERv.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3DERv.png" alt="enter image description here"></a></p>
  
  <p>I understood the library font-awesome need use some another files. My question is : how can/must I add properly theses anothers files in a symfony 3 ? </p>
  
  <p>Thanks !  </p>