def setPreference = Action(parse.json) { request =>
      (request.body \ "key").asOpt[String].map { key =>
          (request.body \ "value").asOpt[String].map { value =>
              SessionPreferences.set(key, value)
              Ok("{success: true}")
          }.getOrElse {
              BadRequest("{success: false, reason: missing 'value'}")
          }
      }.getOrElse {
          BadRequest("{success: false, reason: missing 'key'}")
      }

  }