Update configuration.rb
Update configuration.rb

Require 'URI', because Raven::Configuration#server= requires URI.parse() .

alyssa/raven-ruby,ShakrMedia/raven-ruby,if1live/raven-ruby,zanker/raven-ruby,spredfast/raven-ruby,timcheadle/raven-ruby,nateberkopec/raven-ruby,looker/raven-ruby,sunkencity/raven-ruby,getsentry/raven-ruby,jakecraige/raven-ruby