MERN docs

Hello. Thank you for awesome stack. But it will be cool to have some short tutorial which covers what packages, tricks, main concepts and techniques were used in it. For example, I am newbie in react and redux, and it is hard for me to understand why you are using some package and how you do it (react-hot loader in v2.0.0, for example). Is it possible? And by the way, why do not you use redux-saga? It is cool.