RegisterController.php

use GetStream\StreamChat\Client as StreamClient;

protected function registered($user)
{
  $invite = Invite::firstWhere('email', $user->email);

  $invite->accepted = true;
  $invite->save();

  $client = new StreamClient(
    env('MIX_STREAM_API_KEY'),
    env('MIX_STREAM_API_SECRET'),
    null,
    null,
    9
  );

  $client->updateUser([
    'id' => $user->username,
    'name' => $user->username,
  ]);

  $channel = $client->Channel('messaging', 'Chatroom');
  $channel->addMembers([$user->username]);
}