Install a custom loader with webpacker gem

I am trying to use a Vue.js based material design framework called Vuetify with Rails 5 and the webpacker gem. The styles for this framework are created with the Stylus framework. I followed the instructions on the webpacker github page as to how to install a custom loader but was unable to make it work. Has anyone tried using loaders before and can help me with this?

Here is the stackoverflow question which has more details about the problem which I am facing:-
https://stackoverflow.com/questions/46595583/using-vuetify-with-rails-5-1-4