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: 20211209213849_remove_dangling_user_reactions.rb
    path of file: ./repos/forem/lib/data_update_scripts
    
    the code of the file until where you have to start completion: module DataUpdateScripts
  class RemoveDanglingUserReactions
    def run
      #
    
    def run
      # reactions to users who have been deleted should be removed:
      Reaction
        .where(reactable_type: "User")
        .where.not(reactable_id: User.all.select(:id))
        .delete_all
    end