Added required fields to validatable

lib/devise/models/validatable.rb

@@ -17,6 +17,10 @@ module Devise
       VALIDATIONS = [ :validates_presence_of, :validates_uniqueness_of, :validates_format_of,
                       :validates_confirmation_of, :validates_length_of ].freeze
 
+      def self.required_fields(klass)
+        []
+      end
+
       def self.included(base)
         base.extend ClassMethods
         assert_validations_api!(base)

test/models/validatable_test.rb

@@ -110,4 +110,8 @@ class ValidatableTest < ActiveSupport::TestCase
       Class.new.send :include, Devise::Models::Validatable
     end
   end
+
+  test 'required_fields should be an empty array' do
+    assert_equal Devise::Models::Validatable.required_fields(User), []
+  end
 end