Gemfile.lock comparison

#Compares to Bundler lock files and prints a report
#of which gems have changed version
require "yaml"

old = YAML.load_file("Gemfile.lock.old")
current = YAML.load_file("Gemfile.lock")

old['specs'].each do |elem|
  elem.each do |name, details|
    old_name = name
    old_version = details['version'] 
    current_gem = current['specs'].detect{|e| e.keys.first==old_name}
    current_version = current_gem[old_name]['version']
    puts "#{old_name} changed from #{old_version} to #{current_version}" unless old_version==current_version
  end
end