You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: 20100412000000_add_ok_for_export_to_names.rb
    path of file: ./repos/mushroom-observer/db/migrate
    
    the code of the file until where you have to start completion: # encoding: utf-8
class AddOkForExportToNames < ActiveRecord::Migration
  def self.up
    add_column :
    
  def self.down
    remove_column :names, :ok_for_export
    remove_column :locations, :ok_for_export
    remove_column :location_descriptions, :ok_for_export
    remove_column :name_descriptions, :project_id
    remove_column :location_descriptions, :project_id
  end