Add callback for enqueue()
modify README.md to add callback use of enqueue()
modify README.md to add callback use of enqueue()
Merge branch 'enqueue-callback' of github.com:tvkkpt/coffee-resque into enqueue-callback

Conflicts:
	README.md
Remove redundant lines in README
Rename 'done' to 'callback' to follow the convention
Just add 'args' on stringify call
Add parenthese for stringify call
Merge pull request #38 from tvkkpt/enqueue-callback

Add callback for enqueue()