update method
Update a BlockingModel
Implementation
@override
Future<BlockingModel> update(BlockingModel value) {
  return reference.update(value).then((newValue) {
    fullCache[value.documentID] = newValue;
    return newValue;
  });
}Update a BlockingModel
@override
Future<BlockingModel> update(BlockingModel value) {
  return reference.update(value).then((newValue) {
    fullCache[value.documentID] = newValue;
    return newValue;
  });
}