Mapping plain SQL in Slick to a case class

slickPlainSQL.scala

//https://softwaremill.com/comparing-scala-relational-database-access-libraries/
case class MetroSystemWithCity(metroSystemName: String, cityName: String, 
  dailyRidership: Int)

implicit val getMetroSystemWithCityResult = GetResult(r => 
  MetroSystemWithCity(r.nextString, r.nextString, r.nextInt))

val query = sql"""SELECT ms.name, c.name, ms.daily_ridership
                    FROM metro_system as ms
                    JOIN city AS c ON ms.city_id = c.id
                    ORDER BY ms.daily_ridership DESC""".as[MetroSystemWithCity]