One small suggestion: you might to include the adding of ion tables as part of the installation portion of the user guide. The problem with just running ion_auth.sql through phpmyadmin is that it doesn’t add your CI table prefix.
Since Ben is so busy, I decided to make a few quick edits to the pre-existing sql to include prefixes and I’ll attempt to make a few edits to the library to let it utilize prefixes using a configuration key.
Wouldn’t it make more sense to create an install controller using CI’s Database Forge Class?
http://ellislab.com/codeigniter/user-guide/database/forge.html
Then, we woudn’t have to worry about having a separate .sql file for postgre vs mysql vs mssql since it uses the CI db abstraction layer.