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: rankable.rb
    path of file: ./repos/kitsu-server/app/models/concerns
    
    the code of the file until where you have to start completion: module Rankable
  DEFAULT_RANKINGS = {
    popularity
    
    def update_rankings(rankings = DEFAULT_RANKINGS)
      rankings.each do |output_column, sort_column|
        ids = where.not(sort_column => nil).order(sort_column => :desc).ids
        ids.each_with_index do |id, index|
          where(id: id).update_all(output_column => index + 1)
        end
      end
    end