has 'email' => (
    is        => 'rw',
    isa       => 'Str',
    lazy      => 1,
    builder   => '_lookup_email',
);

sub _lookup_email {
    my $self = shift;
    return $self->_dbh->selectall_array(
        'select email from users where name = ?',
        {},
        $self->name,
    )->[0];
);