multi env hello world using Ciris

MainMulti.scala

package exercise.ciris.qiita1

import ciris.api.Id
import ciris.{ConfigResult, env, withValues, loadConfig}
import ciris.generic._

object MainMulti {
  case class Config(name: String)

  val config: ConfigResult[Id, Config] =
    withValues(env[Option[String]]("APP_ENV")) {
      case Some("PRODUCTION") => loadConfig(env[String]("NAME"))(Config)
      case _                  => loadConfig { Config("local") }
    }
  def main(args: Array[String]): Unit = {
    val greeting = config.result.fold(_.message, c => s"Hello, ${c.name}!")
    println(greeting)
  }
}