title: Goutte Post JSON or set cookie
body: <p>I'm trying to submit a form using Goutte. The form uses jQuery to serialize a form to json and post to an url. After submitting, it updates the browser's cookie.</p>
  
  <p>I either need to:</p>
  
  <ol>
  <li>set the cookie manually in Goutte,</li>
  <li>or send the json post through Goutte so it's cookie jar is updated.</li>
  </ol>
  
  <p>I tried using Goutte's <code>addContent</code> method to create a form and then post it, but it's not sent as JSON, just a regular query string.</p>