Rename Rails 1 style migration names to timestamp filenames

rename_rails_migrations.rb

require 'fileutils'
Dir['./db/migrate/*.rb'].each do |from|
  to = File.join(File.dirname(from),
    "%014d%s" % File.basename(from).match(/^(\d+)(_.*)$/)[1..-1].map.with_index do |f, i|
      0 == i ? f.to_i : f
    end)
  FileUtils.mv(from, to) if from != to
end