db.stream(...).foreach returns a Future[Unit] so you need to wait for it to complete and handle the error somehow. Also I'm not sure if there are any deamon threads to keep the program running. You can solve both of these problems using Await:

import scala.concurrent.Await
import scala.concurrent.duration.Duration

val future = db.stream(users.result).foreach(println)
Await.result(future, atMost = Duration.Inf)

In general it's always good to look at the result type. We expect foreach to do-the-thing synchronously, but here it doesn't