The authentication "server" is the files that would go in tandem with the regular server file when compiled. It's only separated out so you can choose to use it or not. So replacing the files in the auth folder with the regular server folder should work, I think.
Setting the authentication up doesn't look that difficult, but will only be as secure as how you decide to implement it.
Is how it looks to me, I only skimmed through the code for a bit.