[Dev] Installation guide change (Add a user)

[José Alberto]

Hi,

I think this step

     # USERNAME='your-username-here'
     # PASSWORD='your-password-here'
     # useradd -m -g users -G "wheel" -s /bin/bash -p $(openssl passwd 
$PASSWORD) $USERNAME

should be changed as setting the password like that can lead to the
password written in shell history in plain text. I think this would be
better (and simpler):

     # USERNAME='your-username-here'
     # useradd -m $USERNAME
     # passwd $USERNAME

May I change the installation guide wiki page with it?

José Alberto