Get story id from branch name and add pivotal reference to commit message

prepare-commit-msg

#!/usr/bin/env ruby
# 
# Copy this file into .git/hooks and chmod +x
#
branchname = `git branch --no-color 2> /dev/null`[/^\* (.+)/, 1].to_s
PIVOTAL_REFERENCE = /s-(\d+)/i
if story_match = branchname.match(PIVOTAL_REFERENCE)
  story_id = story_match.captures.first
  reference = "[#%s]" % story_id
  `echo "#{reference}"|cat - #{ARGV[0]} > /tmp/out && mv /tmp/out #{ARGV[0]}`
end