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: 20110508145337_cleanup_bug_tables.rb
    path of file: ./repos/openstreetmap-website/db/migrate
    
    the code of the file until where you have to start completion: class CleanupBugTables < ActiveRecord::Migration[4.2]
  def self.up
    rename_column :map_bugs, :date_created, :created_at
    rename_column :map_bugs, :last_changed, :updated_at
    rename_column :map_bugs, :date_closed, :closed_at

    rename_column :map_bug_comment, :date_created, :created_at
    rename_column :map_b
    
  def self.down
    rename_column :map_bug_comment, :body, :comment
    rename_column :map_bug_comment, :author_id, :commenter_id
    rename_column :map_bug_comment, :author_ip, :commenter_ip
    rename_column :map_bug_comment, :author_name, :commenter_name
    rename_column :map_bug_comment, :created_at, :date_created

    rename_column :map_bugs, :closed_at, :date_closed
    rename_column :map_bugs, :updated_at, :last_changed
    rename_column :map_bugs, :created_at, :date_created
  end