Ghost
Code injection, applied site-wide.
1. Open Code Injection
In Ghost Admin, go to Settings → Code injection.
2. Paste into Site Header
Paste this into the "Site Header" box and save.
HTML
<script defer data-site="YOUR_SITE_ID" src="https://api.shonylabs.com/js/YOUR_SITE_ID.js"></script>Only want it on posts, not the homepage? Ghost also has a per-post "Header" code field on each post's settings panel.