public function add($site_env, $username, $password)
{
list($site, $env) = $this->getSiteEnv($site_env);
$workflow = $env->getLock()->add(['username' => $username, 'password' => $password]);
while (!$workflow->checkProgress()) {
// @TODO: Add Symfony progress bar to indicate that something is happening.
}
$this->log()->notice('{site}.{env} has been locked.', ['site' => $site->get('name'), 'env' => $env->id]);
}