Add the following javascript code just before the end of the body tag. 
<script type="text/javascript">
    (function () {
        var nb = document.createElement('script'); nb.type = 'text/javascript'; nb.async = true;
        nb.src = 'http://s.prabir.me/nuget-button/0.1/nuget-button.min.js';
        var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(nb, s);
    })();
</script>
Then add the following html code to get the nuget button rendered. 
<pre class="nuget-button">Install-Package Facebook</pre>
Samples
Fixed Length Sample 
Install-Package Facebook
Full Stretch Sample (default) 
Install-Package SimpleJson