How to add subscribes with mailchimp API

Question

I have a form in index.php file:

<form class="form-inline" action="subscribe.php">
    <input type="email" class="form-control" id="email" placeholder="Your mail" size="30">
    <button type="button" class="btn" id="emailbutton"></button>
</form>

I saw a answer in the site, and I copied it to my subscribe.php file, with changing the API Key and the LIST ID Key:

<?php

$apikey = '<api_key>';
        $auth = base64_encode( 'user:'.$apikey );

        $data = array(
            'apikey'        => $apikey,
            'email_address' => $email,
            'status'        => 'subscribed',
            'merge_fields'  => array(
                'FNAME' => $name
            )
        );
        $json_data = json_encode($data);

        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, 'https://us2.api.mailchimp.com/3.0/lists/<list_id>/members/');
        curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json',
                                                    'Authorization: Basic '.$auth));
        curl_setopt($ch, CURLOPT_USERAGENT, 'PHP-MCAPI/2.0');
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_TIMEOUT, 10);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $json_data);                                                                                                                  

        $result = curl_exec($ch);

        var_dump($result);
        die('Mailchimp executed');
?>

But still nothing happened. I should add a API file or something? and if yes, please provide me a link to this. Thanks for the helping guys!