module Devise::Models::Authenticatable

def self.required_fields(klass)
  []
end

def active_for_authentication?
  true
end

def apply_to_attribute_or_variable(attr, method)
  (self[attr] || send(attr)).try(method)
end

def authenticatable_salt
end

def devise_mailer
  Devise.mailer
end

def downcase_keys
  self.class.case_insensitive_keys.each { |k| apply_to_attribute_or_variable(k, :downcase!) }
end

def inactive_message
  :inactive
end

end
end
@pending_notifications ||= []
def pending_notifications

end
end
devise_mailer.send(n, self).deliver
pending_notifications.each do |n|
def send_pending_notifications

end
pending_notifications << notification
def send_devise_notification(notification)

protected

after_commit :send_pending_notifications

devise :database_authenticatable, :confirmable
class User

deliveries until the after_commit callback is triggered:
you can override send_devise_notification to store the
just after the transaction was committed. To achieve this,
sidekiq, resque, etc), you must add the delivery to the queue
if you are using a queue to deliver e-mails (delayed job,
need to customize the e-mail delivery logic. For instance,
to send a notification/mail. This can be overriden if you
This is an internal method called every time Devise needs

def send_devise_notification(notification, opts={})
  devise_mailer.send(notification, self, opts).deliver
end

def strip_whitespace
  self.class.strip_whitespace_keys.each { |k| apply_to_attribute_or_variable(k, :strip!) }
end

def unauthenticated_message
  :invalid
end

and inactive_message instead.
However, you should not overwrite this method, you should overwrite active_for_authentication?

if a model should be signed in or not.
find_for_authentication are the methods used in a Warden::Strategy to check
Check if the current object is valid for authentication. This method and

def valid_for_authentication?
  block_given? ? yield : true
end