title: How to specify Composer install path?
body: <p>I have this definition:</p>
  
  <pre><code>{
      "repositories": [
          {
              "type": "package",
              "package": {
                  "name": "symfony/sfGuardPlugin",
                  "version": "4.0.2",
                  "dist": {
                      "url": "http://plugins.symfony-project.org/get/sfGuardPlugin/sfGuardPlugin-4.0.2.tgz",
                      "type": "tar"
                  }
              }
          }
      ],
      "require": {
          "symfony/sfGuardPlugin": "4.0.*"
      }
  }
  </code></pre>
  
  <p>I am using Symfony 1, and I'd like to install them on <code>plugins/sfGuardPlugin/</code>. How do I specify this?</p>