require('groupme.php');
function send($group_id, $message) {
    $gm = new GroupMePHP\groupme('APIKEY');
    $gm->messages->create(
        $group_id,
        array("THISISAGUID123", $message)
    );
}
send(12345678, "Hello Group");

require('groupme.php');
function dm($user_id, $message) {
    $gm = new GroupMePHP\groupme('APIKEY');
    $gm->directmessages->create(
        array(
            "source_guid" => "THISISAGUID123",
            "recipient_id" => $user_id,
            "text" => $message
        )
    );
}
dm(12345678, "Hello User");

require('groupme.php');
$gm = new GroupMePHP\groupme('APIKEY');

$index = $gm->groups->index(array());

$group_id = 1234567;
require('groupme.php');
$gm = new GroupMePHP\groupme('APIKEY');
echo json_decode($gm->groups->show($group_id), true)['response']['members'];