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: 20170330041605_add_index_to_topic_status_updates.rb
    path of file: ./repos/discourse/db/migrate
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

class AddIndexToTopicStatusUpdates < ActiveRecord::Migrat
    
  def up
    execute <<~SQL
    CREATE UNIQUE INDEX idx_topic_id_status_type_deleted_at
    ON topic_status_updates(topic_id, status_type)
    WHERE deleted_at IS NULL
    SQL
  end