This suppose to be the code for #Jekyll.

  (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),

  ga('create', 'UA-152619439-1', 'auto');
  ga('send', 'pageview');

Info from #Google #Analytics website provides the following code:

<!-- Global site tag (gtag.js) - Google Analytics -->
<script async src=""></script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());

  gtag('config', 'UA-152619439-1');

Nevertheless, my question was about how to implement the #Jekyll website from GitHub Pages so I wouldn’t have to install it in my computer. I tried to add the files directly to the GitHub repository through GitHub Desktop.