Flawed ID logic on document creation.

We currently set the autogenerated document ID when we initialize the map that holds the json contents https://gitlab.com/npolar/api/mongo/blob/develop/driver.go#L315. However the next step in the process can destroy this id if a "_id" key is present in the json. The document will get inserted with the ID in the JSON but the info object will be stored with the autogenerated ID resulting in a dead reference.