This directory holds subidfs, a FUSE filesystem that gives users
implicit access to their sub-users' files.  For instance, if alice has a
sub-user bob:

	alice:~$ cd /subidfs/home/alice_bob
	alice:/subidfs/home/alice_bob$ ls -l
	-r--r--r--  1 alice_bob users 13492 2006-11-13 02:52 secret_file.txt
	alice:/subidfs/home/alice_bob$ chown alice.users secret_file.txt
	alice:/subidfs/home/alice_bob$ ls -l
	-r--r--r--  1 alice users 13492 2006-11-13 02:52 secret_file.txt
	alice:/subidfs/home/alice_bob$ 

