Use ActiveSupport::Concern.

lib/devise/controllers/helpers.rb

@@ -2,17 +2,16 @@ module Devise
   module Controllers
     # Those helpers are convenience methods added to ApplicationController.
     module Helpers
+      extend ActiveSupport::Concern
 
-      def self.included(base)
-        base.class_eval do
-          helper_method :warden, :signed_in?, :devise_controller?,
-                        *Devise.mappings.keys.map { |m| [:"current_#{m}", :"#{m}_signed_in?"] }.flatten
+      included do
+        helper_method :warden, :signed_in?, :devise_controller?,
+                      *Devise.mappings.keys.map { |m| [:"current_#{m}", :"#{m}_signed_in?"] }.flatten
 
-          # Use devise default_url_options. We have to declare it here to overwrite
-          # default definitions.
-          def default_url_options(options=nil)
-            Devise::Mapping.default_url_options
-          end
+        # Use devise default_url_options. We have to declare it here to overwrite
+        # default definitions.
+        def default_url_options(options=nil)
+          Devise::Mapping.default_url_options
         end
       end
 

lib/devise/models/authenticatable.rb

@@ -27,13 +27,11 @@ module Models
     #    User.find(1).valid_password?('password123')         # returns true/false
     #
     module Authenticatable
-      def self.included(base)
-        base.class_eval do
-          extend ClassMethods
+      extend ActiveSupport::Concern
 
-          attr_reader :password, :current_password
-          attr_accessor :password_confirmation
-        end
+      included do
+        attr_reader :password, :current_password
+        attr_accessor :password_confirmation
       end
 
       # Regenerates password salt and encrypted password each time password is set,

lib/devise/models/confirmable.rb

@@ -29,15 +29,12 @@ module Models
     #   User.find(1).send_confirmation_instructions # manually send instructions
     #   User.find(1).resend_confirmation! # generates a new token and resent it
     module Confirmable
+      extend ActiveSupport::Concern
       include Devise::Models::Activatable
 
-      def self.included(base)
-        base.class_eval do
-          extend ClassMethods
-
-          before_create :generate_confirmation_token, :if => :confirmation_required?
-          after_create  :send_confirmation_instructions, :if => :confirmation_required?
-        end
+      included do
+        before_create :generate_confirmation_token, :if => :confirmation_required?
+        after_create  :send_confirmation_instructions, :if => :confirmation_required?
       end
 
       # Confirm a user by setting it's confirmed_at to actual time. If the user

lib/devise/models/http_authenticatable.rb

@@ -6,9 +6,7 @@ module Models
     # model class responds to authenticate and authentication_keys methods
     # (which for example are defined in authenticatable).
     module HttpAuthenticatable
-      def self.included(base)
-        base.extend ClassMethods
-      end
+      extend ActiveSupport::Concern
 
       module ClassMethods
         # Authenticate an user using http.

lib/devise/models/lockable.rb

@@ -18,14 +18,9 @@ module Models
     #              available when unlock_strategy is :time or :both.
     #
     module Lockable
+      extend ActiveSupport::Concern
       include Devise::Models::Activatable
 
-      def self.included(base)
-        base.class_eval do
-          extend ClassMethods
-        end
-      end
-
       # Lock an user setting it's locked_at to actual time.
       def lock
         self.locked_at = Time.now

lib/devise/models/recoverable.rb

@@ -14,11 +14,7 @@ module Models
     #   # creates a new token and send it with instructions about how to reset the password
     #   User.find(1).send_reset_password_instructions
     module Recoverable
-      def self.included(base)
-        base.class_eval do
-          extend ClassMethods
-        end
-      end
+      extend ActiveSupport::Concern
 
       # Update password saving the record and clearing token. Returns true if
       # the passwords are valid and the record was saved, false otherwise.

lib/devise/models/rememberable.rb

@@ -30,14 +30,11 @@ module Models
     #   # lookup the user based on the incoming cookie information
     #   User.serialize_from_cookie(cookie_string)
     module Rememberable
+      extend ActiveSupport::Concern
 
-      def self.included(base)
-        base.class_eval do
-          extend ClassMethods
-
-          # Remember me option available in after_authentication hook.
-          attr_accessor :remember_me
-        end
+      included do
+        # Remember me option available in after_authentication hook.
+        attr_accessor :remember_me
       end
 
       # Generate a new remember token and save the record without validations.

lib/devise/models/timeoutable.rb

@@ -11,9 +11,7 @@ module Models
     #
     #   timeout_in: the time you want to timeout the user session without activity.
     module Timeoutable
-      def self.included(base)
-        base.extend ClassMethods
-      end
+      extend ActiveSupport::Concern
 
       # Checks whether the user session has expired based on configured time.
       def timedout?(last_access)

lib/devise/models/token_authenticatable.rb

@@ -18,11 +18,10 @@ module Models
     #    User.find(1).valid_authentication_token?('rI1t6PKQ8yP7VetgwdybB')  # returns true/false
     #
     module TokenAuthenticatable
-      def self.included(base)
-        base.class_eval do
-          extend ClassMethods
-          before_save :ensure_authentication_token
-        end
+      extend ActiveSupport::Concern
+
+      included do
+        before_save :ensure_authentication_token
       end
 
       # Generate new authentication token (a.k.a. "single access token").