My last ApplicationJob ever.

application_record.rb

# capture every XXXX_just_later call and create a JustLaterJob 
class ApplicationRecord < ActiveRecord::Base
  self.abstract_class = true
  def method_missing(method, *args, &block)
    ms = method.to_s
    if ms.end_with?('_just_later')
      a = ms[0...-11]
      if respond_to?(a)
        JustLaterJob.perform_later(self, a, *args)
      end
    else
      super(method, *args, &block)
    end
  end
end

just_later_job.rb

class JustLaterJob < ApplicationJob
  queue_as :default
  def perform(e, method, *args)
    e.send(method, *args)
  end
end

message.rb

# that's how you use it
class Message < ApplicationRecord
  belongs_to :user, optional: true
  validates :content, presence: true, allow_blank: false
  after_commit :notify_just_later

  def notify
    SMS.send(user.phone, "got a new message: #{content}")
  end
end