This is a generic question, there are many HCLs. Red Hat has their own, there is one on linuxquestions.org where anyone can add something, linuxhcl.com/ is commonly referenced as the "main" HCL but there really isn't an official one with the exception of Red Hat claiming their own as the official for RHEL systems(don't quote me on the last bit, I have heard that SUSE has their own as well but I couldn't find it) .
If you want to add one to linuxhcl.com all you have to do is go here http://linuxhcl.com/reviews/write
. I would go ask your teacher some clarifications on this.