title: Error in setting up a service using lagom
body: <p>I am nearly replicating the shopping crt example of GitHub. I am getting the following error: </p>
  
  <pre><code>Error:(41, 32) type mismatch;
   found   : akka.actor.typed.ActorRef[com.rddSpTrMS.api.RDDSpTrView]
   required: akka.actor.typed.ActorRef[com.rddSpTrMS.impl.RDDSpTrState.RDDSpTrSummary]
        .ask(reply =&gt; GetRDD(id, reply)
  </code></pre>
  
  <p>to the following lines of code:</p>
  
  <pre><code>override def getRDD(id: String): ServiceCall[NotUsed, RDDSpTrView] = ServiceCall { _ =&gt;
      entityRef(id)
        .ask(reply =&gt; GetRDD(id, reply)
        .map(summary =&gt; convertRDD(id, summary))      )
    }
  </code></pre>
  
  <p>The GetRDD command looks like:</p>
  
  <pre><code>  final case class GetRDD(
      cat_id: String,
      replyTo: ActorRef[RDDSpTrSummary]) extends RDDSpTrCommand
  </code></pre>
  
  <p>Any hints would be very helpful. Happy to provide more lines of code.</p>