Resize OS X El Capitan HD to full size

Got OS X El Capitan running inside VMware Fusion 8. The default drive size is around 40GB and I wanted to change it to 120GB. Disk Utility seems like the tool to do the job but is not working properly. To resize, do:

$ sudo disktuil resizeVolume / R

Reference(s):
 https://themacwrangler.wordpress.com/2015/10/21/resizing-el-capitan-mac-volumes-under-vmware-fusion/