Allow access to guests to search on customers
$acl->allow('guests', 'customers', 'search');
Allow access to guests to search or create on customers
$acl->allow('guests', 'customers', ['search', 'create']);
Allow access to any role to browse on products
$acl->allow('*', 'products', 'browse');
Allow access to any role to browse on any resource
$acl->allow('*', '*', 'browse');