build_configuration_sentence

# File activerecord/lib/active_record/database_configurations.rb, line 187
      def build_configuration_sentence
        configs = configs_for(include_hidden: true)

        configs.group_by(&:env_name).map do |env, config|
          names = config.map(&:name)
          if names.size > 1
            "#{env}: #{names.join(", ")}"
          else
            env
          end
        end.join("\n")
      end