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: 20160517070433_load_default_map_backgrounds.rb
    path of file: ./repos/ekylibre/db/migrate
    
    the code of the file until where you have to start completion: # Load default set of map backgrounds
class LoadDefaultMapBackgrounds < ActiveRecord::Migration[4.2]
  MAP_BACKGROUNDS = [
    { name: 'OpenS
    
  def change
    reference_names = select_values('SELECT reference_name FROM map_backgrounds').uniq
    MAP_BACKGROUNDS.each do |background|
      next if reference_names.include?(background[:reference_name])
      execute 'INSERT INTO map_backgrounds (' + background.keys.join(', ') +
              ', created_at, updated_at) SELECT ' +
              background.values.map { |v| quote(v) }.join(', ') +
              ', CURRENT_TIMESTAMP, CURRENT_TIMESTAMP;'
    end
  end