Registration problem due to unique personnummer

[Gregoire Detrez]

Some problems are starting to appear because of the personnummer being unique: a student who makes a typo in her email address won't be able to register again with the same pn.

The quick-and-dirty solution would be to make the PN not unique. A better alternative could be to add a step in the registration:

1. register with name and email only
2. click on link
3. only once the email is verified, ask for the personnummer.

[Evgeny Kotelnikov]

And also separate registered and unactivated users. Otherwise we wouldn't be able to maintain NOT NULL constraint on PN.

[Gregoire Detrez]

Add a new schema for a simpler registration form (only email)

See #13 and #19

→ <<cset b996db730846>>

[Gregoire Detrez]

Change the signup process (WIP, see #13)

→ <<cset bdca7cab26a9>>

[Gregoire Detrez]

New signup process

Fix #13 Fix #19 Fix #20

→ <<cset 2b92623fa337>>