How to use ActiveRecord::Callbacks with clear separation of responsibilities

email_listener.rb

class EmailListener
  
  def user_created(user)
    UserMailer.welcome_email(user).deliver
  end

end

user.rb

class User < ActiveRecord::Base
  include Wisper::Publisher
  
  ##############################
  # CALLBACKS
  ##############################

  after_create :notify_created

  ##############################
  # PRIVATE METHODS
  ##############################
  
  private

  def notify_created
    publish(:user_created, self)
  end

end

users_controller.rb

class UsersController < ApplicationController

  def create
    @user = User.new(user_params)
    @user.subscribe EmailListener.new

    if @user.save
      # ..
    else
      # ..
    end
  end

  private

  def user_params
    # ..
  end

end