README.md in mongoid-rspec-4.0.1 vs README.md in mongoid-rspec-4.1.0

@@ -259,9 +259,13 @@
 end
 
 RSpec.describe Site do
   it { is_expected.to have_many(:users).as_inverse_of(:site).ordered_by(:email.asc).with_counter_cache }
 end
+
+RSpec.describe Message do
+  it { is_expected.to belong_to(:user).with_optional }
+end
 ```
 
 ### Validation Matchers
 
 ```ruby