title: No Json serializer found
body: <p>I am doing the sample Play project from <a href="https://www.playframework.com/" rel="nofollow">https://www.playframework.com/</a>. I have reproduced the code from the tutorial.</p>
  
  <p>However, on this code from the controller <code>Application</code>:</p>
  
  <pre><code>  def getPersons = Action {
      val persons = DB.query[Person].fetch
      Ok(Json.toJson(persons))
    }
  </code></pre>
  
  <p>I am getting this error:</p>
  
  <pre><code>No Json serializer found for type Stream[models.Person with sorm.Persisted]. Try to implement an implicit Writes or Format for this type.
  </code></pre>
  
  <p>But I think this shouldn't be the case, because an implicit format for this type is already implemented in the model <code>Person</code>:</p>
  
  <pre><code>case class Person(name: String) {
  
    implicit val personFormat = Json.format[Person]
  }
  </code></pre>
  
  <p>And this model is imported in the controller <code>Application</code>.</p>
  
  <p>Is the implicit <code>Format</code> not well defined?</p>