It's very simple
1. Make gist
https://gist.github.com/
2. https://gist.github.com/mishin/a955752a26e3c6baa3b6
Copy Embed html
1. Make gist
https://gist.github.com/
Copy Embed html
3. So, we got <script src="https://gist.github.com/mishin/a955752a26e3c6baa3b6.js"></script>
4. And put this code to end of html