prerequisites.md in dev-lxc-2.4.0

- old
+ new

@@ -9,10 +9,12 @@
 
 ```
 vagrant plugin install vagrant-persistent-storage
 ```
 
-Download and install [ChefDK](http://downloads.chef.io/chef-dk/).
+Download and install [ChefDK](http://downloads.chef.io/).
+
+Run `chef shell-init` to read its usage docs. Then run the appropriate command for your shell.
 
 #### Download dev-lxc-platform
 
 ```
 git clone https://github.com/jeremiahsnapp/dev-lxc-platform.git