Add a bit more detail and polish on the Node.js section

[Arnalv]

I have a problem with the Node.js section as it is to brief and doesn't teach practices such as typing npm init before installing a package, as well as not talking about the REPL.

I would like to be assigned to add a part about the node REPL, and to talk about npm init

[sumn2u]

Sure @Arnalv.