fix(videos): Getting size of non-existent variable

_includes/session/videos.html

@@ -1,5 +1,5 @@
 {% for v in include.videos %}
   {% include session/youtube.html id=v %}
-  {% assign _size = videos | size %}
+  {% assign _size = include.videos | size %}
   {% if forloop.index != _size %}<hr />{% endif %}
 {% endfor %}