Update Prerequisites for the ubunutu install

01_05.md

@@ -1,6 +1,11 @@
 # Learning Jenkins, 01-05: Install Jenkins on Ubuntu
 
 # Prerequisites
+The target system should be running a recent version of the Ubuntu operating system.
+
+You will need to be able to access the system via CLI, most likely over SSH, and via HTTP on port `8080`.
+
+
 You will need to have `root` permission on the target system, specifically so you can run commands using `sudo`.
 
 # Installation