How to create a background task for rake task?

How do I create a background task for a rake task. I want it run every 15 minutes.

My statistik.rake in lib/tasks

desc "Importer statistikker"
namespace :reklamer do
  task :iqmedier => :environment do
          require 'Mechanize'
          agent = WWW::Mechanize.new
          agent.get("http://www.iqmedier.dk")
          form = agent.page.forms.first
          form.Username = 'username'
          form.Password = 'password'
          form.submit

          agent.page.link_with(:href => "/Publisher/Stats").click

          form = agent.page.forms.first
          form.submit

          @stats = agent.page.search('//tr')[-2].search('td').map{ |n| n.text }

          @existing = Reklamer.where(dato: @stats[0]).first
          if @existing.nil?
              Reklamer.create!(:virksomhed => 'Iqmedier', :dato => @stats[0], :unik_klik => @stats[1], :klik => @stats[2], :unik_vis => @stats[3], :vis => @stats[4], :leads => @stats[5], :ordre => @stats[6], :cpc => @sta开发者_如何学JAVAts[7], :earn => @stats[8])
          elsif @existing.dato != Date.today
          Reklamer.create!(:virksomhed => 'Iqmedier', :dato => Date.today, :unik_klik => 0, :klik => 0, :unik_vis => 0, :vis => 0, :leads => 0, :ordre => 0, :cpc => 0, :earn => 0)
          else
            @existing.update_attributes!(:unik_klik => @stats[1], :klik => @stats[2].to_i, :unik_vis => @stats[3], :vis => @stats[4], :leads => @stats[5], :ordre => @stats[6], :cpc => @stats[7], :earn => @stats[8])
          end
  end
end

Depending on your architecture, the simplest way in the Linux world is to set up a cron job:

Create a file in /etc/cron.d and stick this in it:

*/15 * * * *   your_app_user   cd /your/app/path; rake reklamer:iqmedier RAILS_ENV=production

This will run the job every 15 minutes (due to the */15).