add brew install instructions

Readme.md

@@ -1,5 +1,4 @@
-**Clocker** 
----
+# Clocker 
 
 [![Twitter: @clocker_support](https://img.shields.io/badge/contact-@clocker_support-blue.svg?style=flat)](https://twitter.com/clocker_support) [![Build Status](https://travis-ci.org/n0shake/Clocker.svg?branch=master)](https://travis-ci.org/n0shake/Clocker) [![Crowdin](https://badges.crowdin.net/clocker/localized.svg)](https://crowdin.com/project/clocker)
 
@@ -7,12 +6,17 @@
 
 If you'd like to donate, you can do so [here](https://www.paypal.me/AbhishekBanthia). You can find detailed reviews [here](https://www.podfeet.com/blog/2020/07/clocker/) and [slightly older here](https://lifehacker.com/clocker-crams-a-world-clock-into-your-menu-bar-1794709422). Need any help? Open an issue!
 
+## Install
+```shell
+brew install --cask clocker
+```
+
+or
+
 [![Download on the App Store](https://github.com/n0shake/Clocker/blob/v1.2.1/Clocker/Images/MacAppStore.png)](https://itunes.apple.com/us/app/clocker-menubar-world-clock/id1056643111?mt=12)
 
-**Contributing**
----
+# Contributing
 **Clocker** is open for pull requests.
 
-**License**
----
+# License
 Copyright (c) 2020 **Abhishek Banthia**. Released under the MIT License.