Doc: Resizing Boot2Docker Volume with VirtualBox

The Boot2Docker VM ships with a 20G VMDK volume, which can quickly fill up if one is using large images/large numbers of images. This is a step-by-step guide for increasing the B2D volume using VirtualBox and GParted.
That would make sense, but "ISO" here is both redundant and technically wrong.

Simplifying it into "Download a disk partitioning tool" or "Download a partition management tool" would be perfect.