First you need to put a version of Prism in the header. I have used the default CSS from the Cloud flare CDN:
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/prism/1.11.0/themes/prism.min.css">
Then I add the base JS file. If you need other langages you will also need to add them.
<script src="https://cdnjs.cloudflare.com/ajax/libs/prism/1.11.0/prism.min.js"></script>
So for example, here is how you would add markdown support:
<script src="https://cdnjs.cloudflare.com/ajax/libs/prism/1.11.0/components/prism-markdown.js"></script>
The result looks like this:
var person = new Person();
The above was generated using the following code, notice that I include the langauge ID which ghost uses to generate the class="language-javascript"
to add to the pre and code tages
```javascriptvar person = new Person();```