How to Add Mailchimp Subscriber Popup?

Does anyone know how to add this to a theme? I imagine it is supposed to be in the customization for the theme, but adding the code there doesn’t seem to do the trick.

It appears this might be the solution:

By analyzing the output code of the page I noticed that the MailChimp Subscriber Pop-up embed code (file at // ) tries to load the jquery.js file from the root directory of the website.

But there is no jquery.js in the root directory of discourse. They reccomend this fix:

In order to get it work we need to add the jquery.js file to the root directory of the website.

So, how do I do this in discourse?