docs(add-vm) adding info about the user

subjects/add-vm/README.md

@@ -14,10 +14,8 @@ You can download these VM here :
 
 https://assets.01-edu.org/sys
 
-
 ### VirtualBox instructions:
 
-
 For this exercise you need to download the archive : [01_add-vm.tar.gz](https://assets.01-edu.org/sys/01_add-vm.tar.gz).
 
 Extract it in the folder `VirtualBox VMs` which is located in your [home directory](https://en.wikipedia.org/wiki/Home_directory).
@@ -68,4 +66,4 @@ If you forgot to do so and want to make a fresh start, you can always delete the
 
 Since all VMs are based on this one, check that it is working properly by starting and stopping it gracefully.
 
-The password is a single space.
+The username is `root` and the password is a single space.

subjects/add-vm/audit/README.md

@@ -12,6 +12,6 @@
 
 ###### Was the auditee able to make a "snapshot" of the VM?
 
-##### Ask the auditee to start and stop the VM. (reminder the password is a single space)
+##### Ask the auditee to start and stop the VM. (reminding that the user is root and the password is a single space)
 
 ###### Was the auditee able to start and stop the VM?