Selectively load hljs languages

_includes/foot.html

@@ -1,8 +1,11 @@
   {% include about-the-site.html %}
 <script src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/8.5/highlight.min.js"></script>
-<script src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/8.5/languages/vim.min.js"></script>
-<script src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/8.5/languages/haml.min.js"></script>
-<script src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/8.5/languages/scss.min.js"></script>
+
+{% comment %}<!-- https://github.com/highlightjs/cdn-release/tree/master/build/languages -->{% endcomment %}
+{% for lang in page.hljs_languages %}
+<script src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/8.5/languages/{{lang}}.min.js"></script>
+{% endfor %}
+
 <script src="http://cdn.rawgit.com/rstacruz/unorphan/v1.0.1/index.js"></script>
 <script>hljs.initHighlightingOnLoad()</script>
 <script>unorphan('h1, h2, h3, p, li, .unorphan')</script>

rails-forms.md

@@ -1,6 +1,7 @@
 ---
 title: Rails form helpers
 layout: default
+hljs_languages: [haml]
 ---
 
 ## Form builder

vimscript.md

@@ -1,5 +1,6 @@
 ---
 title: Vim script
+hljs_languages: [vim]
 ---
 
 ```vim