=head1 USE

All field keywords beginning with C<html_form_> are passed directly
into the form hash.  Thus, they are really defined in form.tt which
ships with Gantry.

C<html_form_constraint> specifies a Data::FormValidator constraint which
will be checked with either AutoCRUD or CRUD.  The simplest constraints
are regexes, but anything Data::FormValidator understands will work.
Note that you need backticks around the value in the bigtop file, but
inside them you should have unquoted perl code.

=head1 EXAMPLE

To see an example, build:

    bigtop -c example.bigtop all

Change to the newly created Kids directory and look in the form method
in lib/Kids/GEN/Child.pm.