Post-Checkout GIT hook to change database_yml to the name of my current branch.

post-checkout-hook.rb

#!/usr/bin/env ruby

gem 'psych'
require 'psych'

branch = `git branch | grep '*' | cut -c 3-`.chomp
branch.gsub! '/', '_'
branch.gsub! '-', '_'

f = Psych.load_file("config/database.yml")
f["development"]["database"] = "ms_" + branch.to_s

File.open('config/database.yml', 'w') do |file|
  file.write(Psych.dump(f).gsub("---\n", ''))
end

puts "Local development has been switched to: " + branch

Chuck this bad boy in .git/hooks/post-checkout, crack a beer and enjoy.