discourse/app/jobs/regular/send_system_message.rb

require 'image_sizer'
require_dependency 'system_message'

module Jobs

  class SendSystemMessage < Jobs::Base

    def execute(args)
      raise Discourse::InvalidParameters.new(:user_id) unless args[:user_id].present?
      raise Discourse::InvalidParameters.new(:message_type) unless args[:message_type].present?

      user = User.where(id: args[:user_id]).first
      return if user.blank?

      system_message = SystemMessage.new(user)
      system_message.create(args[:message_type])
    end

  end

end