Add a Resources link to tutorial on building dynamic navbars

Hey, folks! I created a blog post about using Jekyll's **data files** to make it easier to build navbars. I think this post would stand amongst the other resources (in terms of usefulness) because: 

* It highlights using Jekyll's data files in a very common use-case.
* It demonstrates the way Jekyll's template-to-site conversion workflow enables a developer to simplify particular tasks, just as a user would expect other CMS's to do the same.
* It has a Napoleon Dynamite gif in it.