TODO: Point on NODE_DEV env. vars

[Student007]

Because learning people will see simplified code every time they will never think about the need of development and production mode. But if you are using GUI generating modules (e.g.) you will have a performance difference between both modes.
So the task is to explain the right use of NODE_ENV within starters apps the right way:

Linux and MacOSX: export NODE_ENV=production
Windows: SET NODE_ENV=production

NODE_ENV=production node index.js