Need to declare before_* callbacks earlier than was being done

Also, can't have self in private method calls
Start tracking student behaviour on registration + ...

... update behaviour table everytime a stab is created.
No need to ensure Account during student registration ...

An associated Account is guaranteed asevery student is required to
provide an unique e-mail address. The uniqueness is ensured by
client side validations

Shell accounts are a legacy of the school offering. No need to support
that now. Which means, that at a later time, we should:
    1. remove the concept of sektions
    2. remove name matching code
    3. remove modal prompting students to think about sektion codes
       (even when they don't have to)