    # File lib/active_record/connection_adapters/abstract/schema_statements.rb, line 121
          def add_column(table_name, column_name, type, options = {})
            add_column_sql = "ALTER TABLE #{table_name} ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
            add_column_options!(add_column_sql, options)
            execute(add_column_sql)
          end