UserApi.scala

  class InvitationApi() extends Controller {
    
    def invite() = Action(parse.json) { request =>
      val payload = request.body.as[UserId]
      val baseUrl = ApplicationConfiguration.get(this).baseUrl
      sendInvitation(payload.userId, baseUrl) match {
        case Success(invitation) => Ok
        case Failure(e) => BadRequest(e.getMessage)
      }
    }
    
  }