Update README.md

Author: cnizzardini

README.md

@@ -21,6 +21,7 @@ This project has been forked from [cnizzardini/cakephp-docker](https://github.co
 | MySQL 8                   | localhost:3607    | db            | [library/mysql:8](https://hub.docker.com/_/mysql) |
 
 - [Installation](#installation)
+- [Mac OS Notes](#mac-notes)
 - [Usage](#usage)
   - [PHP](#php)
   - [MySQL](#mysql)
@@ -40,6 +41,18 @@ That's it! Now just remove `app/*` from [.gitignore](.gitignore). You may also w
 
 > Note: `make init` and `make init.nocache` output interactively, while `make start` and `make up` do not.
 
+## Mac Notes
+
+1. Change your `SHELL` in the Makefile to `/bin/zsh`. This improves various output from the Makefile such as emoji's.
+
+3. Mac ships with an older version of `sed` so install `gnu-sed` for some targets in the Makefile:
+
+```console
+brew install gnu-sed
+```
+
+Then update `sed` to `gsed` in the Makefile.
+
 ## Usage
 
 After install browse to [http://localhost:8080](http://localhost:8080) to see the CakePHP welcome page.