Refactor zsh configs

README.md

@@ -2,11 +2,16 @@
 
 ### prerequisites
 - zsh is installed (scripts are written for zsh)
-- git is installed
+    - ensure ZDOTDIR is set, current idea is put the line below into /etc/zshenv
+    - `export ZDOTDIR="$HOME/.config/zsh"`
 - export the env var `BOX_SETUP_OS` to indicate the operating system
     - options defined in `set_env_vars` file
 - if on macOS, install [homebrew](https://brew.sh/)
 
+##### conditional prerequisites
+- git is installed (if any builds/installs use git)
+- ensure sudo access is configured for the current user
+
 ### script run
 - git clone this repo
 - from the repo's root directory, run `./setup_this_box`