Local Collection synchronisation: Wait until user is logged in

Hey,
I'm having some trouble with my chat application. If I send a message while I am offline, it is added to the local Mongo collection. When I go online, it gets suddenly removed. I find out, that the problem occurs within our allow/deny method:

```
Messages.allow({
insert(userId, doc) {

if(!userId) {
console.log("FORBIDDEN ACCESS");
return false;
}

[....]

return true;
});
```

In this case, userId isn't set and the message gets removed. Maybe we should wait until the user is logged in again and then starting sync the collection data?