Ember.js - multiple checkboxes - pass values to queryParam

I have a project setup like in the following Twiddle

http://ift.tt/2jCKZpD

I'm trying to pass the language.code to the language queryParam for each selected language. In the actual project I'm using http://ift.tt/2auwrET and I've managed to do this with an action bound to the input but on the page refresh the checkboxes values won't stick.

Is there a way to achieve this?