Quotatool is a utility to set filesystem quotas from the commandline. Most quota-utilities are interactive, requiring manual intervention from the user. Quotatool on the other hand is not, making it suitable for use in scripts and other non-interactive situations. This is very useful to edit disk quotas from scripts.
Install quota tools using the following command
sudo apt-get install quota quotatool
Edit /etc/fstab and add usrquota and grpquota options to the mount point which contains the home directories. For me this was the root mount point, but it will depends on how you did your partitoning (it could be that you made a separate mount point for /home).
sudo gedit /etc/fstab
The entry should read something like:
# /dev/hda1 UUID=4ea80ca3-37b7-447e-831a-700a38627029 / ext3 defaults,errors=remount-ro,usrquota,grpquota 0 1
Finish setup with the following series of commands
sudo touch /quota.user /quota.group
sudo chmod 600 /quota.*
sudo mount -o remount /
sudo quotacheck -avugm
sudo quotaon -avug
You can also use webmin to configure this through GUI.