docs: add to do and usage sections to README.md

Author: toobuntu

README.md

@@ -6,7 +6,7 @@
 
 # Babble
 
-An upgrade routine for Homebrew, Mac App Store and macOS
+An upgrade routine for Homebrew, Mac App Store and macOS, written in shell.
 
 ## Example session
 
@@ -23,6 +23,20 @@ curl --silent "https://raw.githubusercontent.com/toobuntu/babble/main/bbl" --out
 
 Change `<path>` to the path of your choice. `"$HOME/Downloads"`, `"$HOME/bin"` and `"$HOME/devel"` are all common possibilities.
 
+## Usage
+
+```sh
+bbl
+```
+
+## To do
+
+- Use a configuration file to supply a list of GUI apps which should be quit prior to upgrading them and restarted after the upgrade is completed.
+- Remove extraneous code comments.
+- Only run `brew upgrade` if `brew outdated` reports something upgradable, similar to how `mas` is already handled in Babble.
+- Do not attempt to upgrade the terminal being used to run Babble itself.
+
+
 ---
 
 #### Babble uses the following open source icons: