jquery-datatables-rails sort arrows not showing up in development environment

Perhaps someone will present a better answer. This is how I fixed it.

I got rid of the gem. Downloaded the javascript and css files from the datatables website:

• jquery.dataTables.min.css
• jquery.dataTables.min.js

Put these files in vendor/assets/stylesheets and vendor/assets/javascripts respectively.

I downloaded the missing images from here and stuck them in my vendor/assets/images folder that I created.

I did a replace all on the text in jquery.dataTables.min.css and replaced "/images/" with "/assets/"

And that fixed it. Hope this helps someone.