gistfile1.scala

    for {
      res <- collection.update(Json.obj("slug" -> idea_slug, "user_id" -> Json.obj("$ne" -> vote.user_id)),
        Json.obj("$addToSet" -> Json.obj(addType -> vote),
          "$pull" -> Json.obj(removeType -> Json.obj("user_id" -> vote.user_id)),
          "$addToSet" -> Json.obj("metrics.attachedUsers" -> vote.user_id))
        , getLastError, false)
      idea <- findOne(Json.obj("slug" -> idea_slug))
    } yield {
      idea
    }