// tests
    public function signUpSuccessfull(AcceptanceTester $I)
    {
        $I->fillField('#firstName', 'Carlos');
        $I->fillField('#lastName', 'Alarcón');
        $I->fillField('#Born','1980-05-17');
        $I->selectOption('#country','Chile');
        $I->haveHttpHeader('Content-Type', 'application/json');
        $I->sendPOST('model/currency_model.php', ['country_id' => '1']);
        $I->canSeeResponseCodeIs(200);
        $I->seeResponseIsJson();
        $I->seeInField('#currency', 'Chilean peso');
     }