jQuery(...).fitVids error

on www.coventrycreaions.com one of the errors we get is:

jQuery.Deferred exception: jQuery(...).fitVids is not a function TypeError: jQuery(...).fitVids is not a function
at HTMLDocument.<anonymous>

What component needs to be loaded to get fitVids installed?

This script is used for the videos popup, you can find this script at the end of layout file:
ROOT/template/gk_storefront/layouts/default.php

// Target your .container, .wrapper, .post, etc.
 jQuery("body").fitVids();