Migration Foreign key problem

GruppoDpiTable
id_gruppo and id_dpi must have 'unsigned' => true,

PHP Code:

class GruppoDpiTable extends Migration
{
    public function up()
    {
        $this->forge->addField([
            'id' => [
                'type'          => 'INT',
                'unsigned'      => true,
                'auto_increment' => true,
            ],

            'id_gruppo' => [
                'type' => 'INT',
                'null' => false,
                'unsigned' => true,
            ],

            'id_dpi' => [
                'type' => 'INT',
                'null' => false,
                'unsigned' => true,
            ],
            'created_at datetime default current_timestamp',
            'updated_at datetime default NULL',
            'deleted_at datetime default NULL',
        ]);

        $this->forge->addForeignKey('id_gruppo','gruppo','id','NO ACTION','NO ACTION');
        $this->forge->addForeignKey('id_dpi','dpi','id','NO ACTION','NO ACTION');

        $this->forge->addKey('id', true);
        $this->forge->createTable('gruppo_dpi');
      
    }

    public function down()
    {
        $this->forge->dropTable('gruppo_dpi');
    }
}