Add cask for Vienna RSS reader
user
```ruby
class ViennaRss < Cask
  url 'http://downloads.sourceforge.net/vienna-rss/Vienna3.0.0_beta11.tgz'
  homepage 'http://www.vienna-rss.org'
  version '3.0.0_beta11'
  sha1 'c1530387fb471331ed3947994e2071151e8d471b'
end
```
assistant