public <T> UpdateResults updateFirst(final Query<T> query, final UpdateOperations<T> ops) {
        return ds.updateFirst(query, ops);
    }
Ensures (creating if necessary) the index including the field(s) + directions; eg fields = "field1, -field2" ({field1:1, field2:-1})
lts-core/src/main/java/com/github/ltsopensource/store/mongo/MongoTemplate.java