define_callbacks

# File activerecord/lib/active_record/associations/builder/association.rb, line 77
    def self.define_callbacks(model, reflection)
      if dependent = reflection.options[:dependent]
        check_dependent_options(dependent, model)
        add_destroy_callbacks(model, reflection)
        add_after_commit_jobs_callback(model, dependent)
      end

      Association.extensions.each do |extension|
        extension.build(model, reflection)
      end
    end