README.md in hashid-rails-0.4.0 vs README.md in hashid-rails-0.4.1

@@ -27,9 +27,11 @@
 
 ```shell
 $ gem install hashid-rails
 ```
 
+> Note: This gem is not yet compatible with Rails 5.
+
 ## Basic Usage
 
 Just use `Model#find` passing in the hashid instead of the model id.
 
 ```ruby