Ignoring a directory using ack's .ackrc

I'm not sure what it's for, but the code I'm working on has a bunch of folders called "save.d," it looks like they're used for some sort of version control (we also have .svn folders).

How can I update my .ackrc file to ignore those directories by default?

My .ackrc is currently

--type-set=inc=.inc
--ignore-dir=pear
--type-set=tpl=.tpl

Our folder structure can look like:

program/parsers/save.d
program/modules/save.d

Adding another line --ignore-dir=save.d did the trick