It would be nice if createIndex ran in the background as default

Hello,

We have been caught out by indexes running in the foreground a few times causing impact to our customers whilst waiting for a index creation.

It would be nice if "background : true" was the default option on a index creation unless otherwise specified.

So far we have not found a reason to run a create Index in the foreground as it causes a lock on the database.

Thanks,
Luke