findByIds = async function(collection, ids, context) {
  
  // get documents
  const documents = await Connectors.find(collection, { _id: { $in: ids } });

  // order documents in the same order as the ids passed as argument
  const orderedDocuments = ids.map(id => _.findWhere(documents, {_id: id}));

  return orderedDocuments;
}
@summary Find by ids, for DataLoader, inspired by https://github.com/tmeasday/mongo-find-by-ids/blob/master/index.js