Fix invalid bulk operation from MongoDB when adding empty array
Fix invalid bulk operation from MongoDB when adding empty array

Currently we allow for empty arrays to be added to the queue,
apparently MongoDB is a bit sensitive about that and throws an error.

This was discovered in the tests and the solution was discovered here:
https://github.com/toymachiner62/node-mongo-seeds/issues/6

A patch to the upsteam repo will also be made to fix this.

feedhenry/fh-mbaas-api,feedhenry/fh-mbaas-api