README.md in devise-token_authenticatable-0.4.9 vs README.md in devise-token_authenticatable-0.4.10

@@ -45,9 +45,10 @@
 This gem can be configured as shown in the following:
 
 ```ruby
 Devise::TokenAuthenticatable.setup do |config|
   # enables the expiration of a token after a specified amount of time,
+  # requires an additional field on the model: `authentication_token_created_at`
   # defaults to nil
   config.token_expires_in = 1.day
 
   # set the authentication key name used by this module,
   # defaults to :auth_token