my $admin_only = $r->under('/admin');
$admin_only->get('*')->to(
    cb => sub {
        my $self = shift;
        $self->redirect_to('/login') and return 0 unless ($self->is_user_authenticated);
        return 1;
    },
    wrapper => 'layouts/admin.tt',
);

$admin_only->get('dashboard')->to('admin#dashboard');
$admin_only->root->to('admin#dashboard');