module Devise::Models::Validatable

def self.included(base)
  base.extend ClassMethods
  assert_validations_api!(base)
  base.class_eval do
    validates_presence_of   :email, :if => :email_required?
    validates_uniqueness_of :email, :allow_blank => true, :if => :email_changed?
    validates_format_of     :email, :with  => email_regexp, :allow_blank => true, :if => :email_changed?
    validates_presence_of     :password, :if => :password_required?
    validates_confirmation_of :password, :if => :password_required?
    validates_length_of       :password, :within => password_length, :allow_blank => true
  end
end