user_observer.rb

class UserObserver < ActiveRecord::Observer

  def after_create(user)
    user.reload
    UserMailer.deliver_signup_notification(user)
  end

  def after_save(user)
    user.reload
    UserMailer.deliver_activation(user) if user.recently_activated?
    UserMailer.deliver_forgot_password(user) if user.recently_forgot_password?
    UserMailer.deliver_reset_password(user) if user.recently_reset_password?
  end

end