Added to_url method in string core extension

Hi Guys,

I just submitted a patch "Added to_url method in string ".

"webonrails.com".to_url => "http://webonrails.com"

"http://webonrails.com".to_url => "http://webonrails.com"

Could someone please review this patch?
https://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/2744-added-to_url-method-in-string

Akhil,