The blackboard has some racy multi-document updates, like creating a new puzzle, then adding that puzzle to its owning round. MongoDB 4.0 supports multi-document transactions. Once Meteor supports it, we should use transactions for these updates.
Blocked by meteor/meteor-feature-requests#269 and meteor/meteor-feature-requests#311.
The blackboard has some racy multi-document updates, like creating a new puzzle, then adding that puzzle to its owning round. MongoDB 4.0 supports multi-document transactions. Once Meteor supports it, we should use transactions for these updates. Blocked by meteor/meteor-feature-requests#269 and meteor/meteor-feature-requests#311.