Update the instruction of enables two-factor-backupable on README

README.md

@@ -174,13 +174,13 @@ Rails.application.config.filter_parameters += [:otp_attempt]
 ## Backup Codes
 Devise-Two-Factor is designed with extensibility in mind. One such extension, `TwoFactorBackupable`, is included and serves as a good example of how to extend this gem. This plugin allows you to add the ability to generate single-use backup codes for a user, which they may use to bypass two-factor authentication, in the event that they lose access to their device.
 
-To install it, you need to add the `:two_factor_backupable` directive to your model.
+To install it, you either add the `:two_factor_backupable` directive to your model
 
 ```ruby
 devise :two_factor_backupable
 ```
 
-You'll also be required to enable the `:two_factor_backupable` strategy, by adding the following line to your Warden config in your Devise initializer, substituting :user for the name of your Devise scope.
+or by adding the following line to your Warden config in your Devise initializer, substituting :user for the name of your Devise scope.
 
 ```ruby
 manager.default_strategies(:scope => :user).unshift :two_factor_backupable