Add Sketch Up (version 8) Cask
user
```ruby
class SketchUp < Cask
  url 'http://dl.trimble.com/sketchup/SketchUpMEN.dmg'
  homepage 'http://www.sketchup.com/intl/en/'
  version '8'
  sha1 '0dbfc19d64119fee86b38bc757b0d2431eef01e0'

  link :app, 'SketchUp.app'
end
```
assistant