<?php

require 'vendor/Emma.php';
$account_id = 1721615;
$public_key = '9b7ceb72fef20670294d';
$private_key = '9ea5894c4af8e1364f43';
$emma = new Emma($account_id, $public_key, $private_key);
$email = $_POST['email'];
$zip_code = $_POST['zip'];
$group_id = $_POST['group_id'];
try {
    $member = array();
    $member['email'] = $email;
    $member['fields'] = array('postal_code' => $zip_code);
    $member['group_ids'] = array($group_id);
    $req = $emma->membersAddSingle($member);
    echo $req;
} catch (Emma_Invalid_Response_Exception $e) {
    exit($e->getMessage());
}