Steps to repro:
Register user 'foo'
Try to register another user 'foo'
The following error happens:
A web handler threw an exception. Details:
user error (SQLite3 returned ErrorConstraint while attempting to perform finalize.)
I think it's the "login" colum uniqueness constraint that's triggering this error.
However, I think the expected behavior in this case would be to throw a snap DuplicateLogin error. This is how createUser is supposed to work (http://hackage.haskell.org/packages/archive/snap/latest/doc/html/Snap-Snaplet-Auth.html) but perhaps registerUser doesn't work the same way?
Described the same bug better in issue #3 so closing this one.