    # File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 678
          def remove_references(*args)
            options = args.extract_options!
            polymorphic = options.delete(:polymorphic)
            args.each do |col|
              @base.remove_column(@table_name, "#{col}_id")
              @base.remove_column(@table_name, "#{col}_type") unless polymorphic.nil?
            end
          end