add symfony live london video

Author: igorw

source/media.html

@@ -5,6 +5,9 @@
 ---
 {% block content %}
 <div class="media">
+    <h2>Symfony Live London 2013</h2>
+    <iframe width="720" height="540" src="//www.youtube.com/embed/QY8mL6WARIE?rel=0" frameborder="0" allowfullscreen></iframe>
+
     <h2>Symfony Usergroup Zürich</h2>
     <script async class="speakerdeck-embed" data-id="6f7005900dc3013147e062d706362dec" data-ratio="1.33333333333333" src="//speakerdeck.com/assets/embed.js"></script>