Please take a note, that this is only brain shortcut for my personal use.
It won't tell you how to install and configure delayed job on your computer.
At first change these settings inside delayed_job.rb
Delayed::Worker.delay_jobs = true
Delayed::Worker.sleep_delay = 15
After this just restart Rails application and Delayed Job process:
RAILS_ENV=development script/delayed_job stop
RAILS_ENV=development script/delayed_job start