Add Docker for Mac Beta (1.12.1.11525) (#2531)

Casks/docker-beta.rb

@@ -0,0 +1,25 @@
+cask 'docker-beta' do
+  version '1.12.1.11525'
+  sha256 '95cdef690943272b00f701c06f1ef4954c0cae7a3a454e91f1d5cad407252e1f'
+
+  url "https://download.docker.com/mac/beta/#{version}/Docker.dmg"
+  appcast 'https://download.docker.com/mac/beta/appcast.xml',
+          checkpoint: 'fcfc6aa7674b26ff0ee1131fcda26dd1be14be88e666fabe88a631ba591bf231'
+  name 'Docker for Mac Beta'
+  homepage 'https://www.docker.com/products/docker'
+  license :gratis
+
+  auto_updates true
+
+  app 'Docker.app'
+
+  uninstall quit: 'com.docker.docker'
+
+  zap delete: [
+                '~/.docker',
+                '~/Library/Caches/com.docker.docker',
+                '~/Library/Containers/com.docker.docker',
+                '~/Library/Preferences/com.docker.docker.plist',
+                '~/Library/Group Containers/group.com.docker',
+              ]
+end