title: Bundle registering inside a vendor bundle
body: <p>I dont understand the bundle architecture correcty.
  I created a bundle which parent is the FOSUserBundle. I want to use my created SHN/UserBundle inside other symfony2 installations. </p>
  
  <p>Inside a target application i receive a </p>
  
  <pre><code>LogicException: Bundle "SHNUserBundle" extends bundle "FOSUserBundle", which is not registered.
  </code></pre>
  
  <p>I mean i extend the fosuserbundle which should be automatically registered because my SHN/UserBundle uses it?</p>
  
  <p>Where is my thinking mistake?</p>
  
  <p><strong>/src/SHN/UserBundle/composer.json:</strong></p>
  
  <pre><code>"name" : "SHN/UserBundle",
  "description" : "Overwrites the FOS Userbundle with some futures",
  "type" : "symfony-bundle",
  "authors" : [{
      "name" : "Timo Linde",
      "email" : "timo.linde@shn-germany.de",
      "role" : "Developer"
  }],
  "keywords" : [
      "fos-userbundle extend"
  ],
  "license" : [
      "proprietary"
  ],
  "require" : {
      "php": "&gt;=5.3.3",
      "friendsofsymfony/user-bundle": "~1.3"
  },
  "autoload" : {
      "psr-0" : {
          "SHN\\UserBundle" : ""
      }
  },
  "target-dir" : "SHN/UserBundle",
  </code></pre>