migration helper to migrate existing data to a target language after adding globalize2 to an existing project

globalize2_migration_helper.rb

module Globalize2MigrationHelper
  
  def migrate_existing_data_to_language(model, target_language)
    say "migrating translated attributes of model '#{model}' to language '#{target_language}'"
    
    # set language to use
    I18n.locale = target_language
    
    # iterate over all records
    for object in model.all
      
      # iterate over translated attributes
      for attribute in model.translated_attribute_names
        
        # fill in original value
        # say "setting '#{model}.#{attribute}' to '#{object[attribute]}'"
        object.send(:"#{attribute}=", object[attribute])
      end
      
      # and save the object without validation
      object.save_with_validation(false)
    end
  end
  
end

migration_file.rb

require 'globalize2_migration_helper'

class AddGlobalize2TranslationTablesToModels < ActiveRecord::Migration
  extend Globalize2MigrationHelper
  
  def self.up
    Book.create_translation_table! :name => :string
    migrate_existing_data_to_language(Book, :de)
  end

  def self.down
    Book.drop_translation_table!
  end
        
end