Add Homebrew cask install option for MacOS. (#1357)

readme.md

@@ -38,7 +38,12 @@ this [wiki page](https://wiki.archlinux.org/index.php/Arch_User_Repository#Insta
 
 ### MacOS
 
-If you get an error "is damaged and can’t be opened." when launching the app, run the following in the Terminal:
+You can install the app using Homebrew:
+```bash
+brew install --cask https://raw.githubusercontent.com/th-ch/youtube-music/master/youtube-music.rb
+```
+
+If you install the app manually and get an error "is damaged and can’t be opened." when launching the app, run the following in the Terminal:
 
 ```bash
 xattr -cr /Applications/YouTube\ Music.app

youtube-music.rb

@@ -0,0 +1,28 @@
+require 'json'
+require 'open-uri'
+
+cask "youtube-music" do
+  desc "YouTube Music Desktop App"
+  homepage "https://github.com/th-ch/youtube-music"
+
+  # Fetch the latest release version from GitHub API
+  latest_release = JSON.parse(open("https://api.github.com/repos/th-ch/youtube-music/releases/latest").read)['tag_name']
+  version latest_release
+
+  base_url = "https://github.com/th-ch/youtube-music/releases/download/#{latest_release}/YouTube-Music-#{latest_release.delete_prefix('v')}"
+  file_extension = Hardware::CPU.arm? ? "-arm64.dmg" : ".dmg"
+  url "#{base_url}#{file_extension}"
+
+  # TODO checksum
+  sha256 :no_check
+
+  app "YouTube Music.app"
+
+  postflight do
+    print("Removing quarantine attribute from YouTube Music.app.\n")
+    system "xattr -cr '/Applications/YouTube Music.app'"
+  end
+
+  auto_updates true
+
+end