Thank you for pointing me in the right direction.
Here is my code for anyone else that may have the same issue
public function register()
{
$this->loadModel('Users');
$user = $this->Users->newEmptyEntity();
if ($this->request->is('post')) {
$formdata = $this->request->getData();
$formdata['role'] = 'user';
$user = $this->Users->patchEntity($user, $formdata);
if ($result = $this->Users->save($user)) {
$this->Authentication->setIdentity($result);
$this->Flash->success(__('The user has been saved.'));
return $this->redirect(['action' => 'index']);
}
$this->Flash->error(__('The user could not be saved. Please, try again.'));
}
$this->set(compact('user'));
}