bulk_updater.rb

class BulkUpdater
  def bulk_update(models)
    errors = {}
    models.each do |model_id, model_attrs|
      model = self.class.find(model_id)
      unless model.update_attributes(model_attrs)
        errors[model_id] = model.errors
      end
    end
    errors
  end
end

ActiveRecord::Base.include BulkUpdater