Add Not Tetris 2 cask
user
```ruby
class NotTetris < Cask
  version '2'
  sha256 'ddb4df7f9169e1a03cb5f81e67b972cca4470e4925973af452f6e467830aaea8'

  url 'http://stabyourself.net/dl.php?file=nottetris2/nottetris2-osx.zip'
  homepage 'http://stabyourself.net/nottetris2/'
  license :oss

  app 'Not Tetris 2.app'
end
```
assistant