Add cask for MySQL Workbench
user
```ruby
class MysqlWorkbench < Cask
  url 'http://cdn.mysql.com/Downloads/MySQLGUITools/mysql-workbench-gpl-5.2.47-osx-i686.dmg'
  homepage 'http://www.mysql.com/products/workbench'
  version '5.2.47'
  sha1 '54b814b418ce8513efdf2a1ac48f4deace867dc3'
  link 'MySQLWorkbench.app'
end
```
assistant