The extracted auth module used by the linkdemo app, as per code in Chapter 9 of Lisp Webtales.
This code needs to exist in your Quicklisp local-projects directory for the Ch.9 code in my other repo, webtales, to work.
(If you use the commit before that, you won't need this, as at that point the code here is contained in that repo.
This repo demonstrates how to pull out code to an independent module in restas).