TODO

Known bugs and missing features:

- prevent creation of duplicate persons (based on first name, last name and
  date of birth)
- also prevent entry of reversed last name and first name (how to deal with it?
  offer to revert existing entry?)
- remove leading and trailing spaces from names and other input fields or at
  least prevent their creation

Pending security measures:

- use hashes instead of IDs for database objects in forms to prevent the
  database from being scraped by enumeration of IDs.
- the same would prevent editing records not belonging to the current user.
- replace the authentication by birthday by a confirmation by email mechanism,
  for editing existing entries and registering new entries. The user has to
  confirm his editing by clicking on a link in the received confirmation email.