change_table_comment

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 516
        def change_table_comment(table_name, comment_or_changes) # :nodoc:
          clear_cache!
          comment = extract_new_comment_value(comment_or_changes)
          execute "COMMENT ON TABLE #{quote_table_name(table_name)} IS #{quote(comment)}"
        end