Merge pull request #18 from fddayan/master

Deamonize clockwork
Include Sidekiq as a job queueing suggestion.
Merge pull request #19 from cseeger/patch-1

Include Sidekiq as a job queueing suggestion.
Added a section to the readme

Clarified how to load the entire Rails app
Merge pull request #20 from mbhnyc/master

Adding a clarifying section to the readme on loading the entire Rails environment
made `clockwork -h` works. Usage is now like `clock <clock.rb> or clockwork --daemon [options] start|stop|restart|run`