Need help understanding last part of ember.js tutorial

I am in the process of learning ember.js to create my first application with a rails backend.

I used the ember.js tutorial located at the following link:

http://ift.tt/1S96chd

Instead of using mirage as the data source, I locally created a rails api so that I can go through the pains of learning how to set up the setup the ActiveModelAdapter.

I was able to complete all but the very last part of the tutorial. I am not sure where to place the code given that the code is meant to be used with mirage and not ActiveModelAdapter.

I am hoping someone can give me an idea of where I am supposed to place this code so I can attempt to understand it. The code can be found at the following link:

http://ift.tt/1q4l0XM

It is the finally piece of code at the bottom of the page labeled app/mirage/config.js

Any help would be greatly appreciated.

Thanks