luminarium plug

welcome/challenge/DESCRIPTION.md

@@ -1,3 +1,6 @@
 The actual files comprising the challenge live in the `/challenge` directory.
 Unlike previous challenges, which automatically ran when the terminal was opened, this challenge requires you to invoke the `/challenge/solve` program directly!
 Just by running it in a terminal, you will get the flag!
+
+**NOTE:** This challenge, and the challenges below, begin to assume knowledge of the Linux commandline.
+If you happen to lack this knowledge, we recommend you first complete the [Linux Luminarium](/linux-luminarium), then resume this module!