NAS, well, maybe not quite, as at the moment we don't have any kind of user or share management.
What it does enable is network drive sharing.
Yes, you can just plug in an external drive, as long as it's FAT32 or NTFS formatted and then share what's on the drive.
The drive will auto mount, so you'll see something like /mnt/drive_name if the drive has a label, if not it'll appear as /mnt/1_usb_2 or something similar.
Both the FTP server and SAMBA will go directly to the /mnt/ directory and you'll be able to see any drives there.
You can change the password, but currently not the username.
We'll be adding more functionality to this in the future, but everything is working.