Do not run yaourt as root/sudo

Signed-off-by: Chris Fordham <chris@fordham-nagy.id.au>

docs/installation/archlinux.md

@@ -42,7 +42,7 @@ is all that is needed.
 
 For the AUR package execute:
 
-    $ sudo yaourt -S docker-git
+    $ yaourt -S docker-git
 
 The instructions here assume **yaourt** is installed. See [Arch User
 Repository](https://wiki.archlinux.org/index.php/Arch_User_Repository#Installing_packages)