Document how to do simple dependency injection

There are usually three main categories of stubbing when dealing with network requests:

1. stubbing out the api doing the actual network calls using a link seam
2. stubbing out the api doing the actual network calls using dependency injection of some sort
3. stubbing out the network layer in the underlying engine (browser or Node)

Presently we only have one article covering the first option, and very little on the two next approaches. We should create a small how-to for the article section that covers how to do basic (no framework) dependency injection.

I have already written a lot of text that could serve as the basis for such an article.

• Testing an ES6 class that relies on jQuery
• Opening up a SUT for injecting dependencies