```ruby
cask :v1_1 => 'dockertoolbox' do
  version '1.9.0a'
  sha256 '45c9447345a5b91aa8b120172a5b3621e0cce34a76e9e577beda29364d8367a0'

  url "https://github.com/docker/toolbox/releases/download/v#{version}/DockerToolbox-#{version}.pkg"
  appcast 'https://github.com/docker/toolbox/releases.atom'
  name 'Docker Toolbox'
  homepage 'https://www.docker.com/toolbox'
  license :apache

  pkg "DockerToolbox-#{version}.pkg"

  postflight do
    set_ownership '~/.docker'
  end

  uninstall :pkgutil => [
                         'io.boot2dockeriso.pkg.boot2dockeriso',
                         'io.docker.pkg.docker',
                         'io.docker.pkg.dockercompose',
                         'io.docker.pkg.dockermachine',
                         'io.docker.pkg.dockerquickstartterminalapp',
                         'io.docker.pkg.kitematicapp',
                        ]

  depends_on :cask => 'virtualbox'
end
```

Update Docker Toolbox to 1.9.0b
user
```ruby
cask :v1_1 => 'dockertoolbox' do
  version '1.9.0b'
  sha256 'dc8c2df85154e0604aca331dda5b6a0711d79f7f7fcd8df0a92bd712bf704811'

  url "https://github.com/docker/toolbox/releases/download/v#{version}/DockerToolbox-#{version}.pkg"
  appcast 'https://github.com/docker/toolbox/releases.atom'
  name 'Docker Toolbox'
  homepage 'https://www.docker.com/toolbox'
  license :apache

  pkg "DockerToolbox-#{version}.pkg"

  postflight do
    set_ownership '~/.docker'
  end

  uninstall :pkgutil => [
                         'io.boot2dockeriso.pkg.boot2dockeriso',
                         'io.docker.pkg.docker',
                         'io.docker.pkg.dockercompose',
                         'io.docker.pkg.dockermachine',
                         'io.docker.pkg.dockerquickstartterminalapp',
                         'io.docker.pkg.kitematicapp',
                        ]

  depends_on :cask => 'virtualbox'
end
```
assistant