Could you please recommend tutorials on developing one's own authentication mechanisms, without the use of industrial-strength plugins?
Is this tutorial from 2006 obsolete?
I spent several person-days trying to install and use restful_authentication, but it was mostly a frustrating, labor-intensive exercise in futility. [1, 2] I then found this prescient article by David Heinemeier Hansson from 2005:
I don't share his philosophical issues with pluggable engines, but in practice, he seems to have been spot on. Impressive!
 The current issues are FixtureClassNotFound errors in the out-of-the-box unit tests on Debian; I've tried Ruby 1.87 and 1.9.1, each with two variations of restful-authentication:
(Why are those different, anyway?) FWIW, after some minor bug-fixing, the plugin works fine on Mac OS X.
 I've also had headaches with git, which has a steep learning curve, no matter how vehemently Linus decrees otherwise.