Most of the config

http4sStuff.scala

```    
//...


  private val nThreads = Runtime.getRuntime.availableProcessors * 2
  private val executorService = Executors.newFixedThreadPool(nThreads)
  implicit val executionContext: ExecutionContextExecutorService = ExecutionContext.fromExecutorService(executorService)

  implicit val cs: ContextShift[IO] = IO.contextShift(ec)
  implicit val timer: Timer[IO] = IO.timer(ec)

  //Here we do a query using doobie
  val domainRoutes: HttpRoutes[IO] = DomainRoutes.routes(..., ...)

  val httpApp = Router(
    "/" -> (domainRoutes)
  ).orNotFound

  BlazeServerBuilder[IO]
    .bindHttp(port, host)
    .withExecutionContext(ec)    
    .withWebSockets(false)
    .withHttpApp(httpApp)
    .resource  


///somewhere else  this is how we create the transactor, we use a Blocker[IO]

def transactorFrom(config: Db)(implicit be: Blocker): Resource[IO, HikariTransactor[IO]] = {
    HikariTransactor.newHikariTransactor[IO](
      config.driver,
      config.url,
      config.user,
      config.password,
      ExecutionContext.fromExecutorService(Executors.newFixedThreadPool(10)),
      be
    )
  }


```