Tour of the client app

We're not going to be building a client app from scratch in this course. This is because I assume you know how to build a Vue.js SPA already, and so I don't want to waste time going over the basics again.

So I've gone ahead and laid down the main structure of the client app. However, a lot of the features, like the application state and authentication, don't yet work. So those are the parts that we'll obviously be implementing together.