Migrate Aquamacs 2.5 cask from homebrew-cask.
user
```ruby
class Aquamacs25 < Cask
  url 'http://braeburn.aquamacs.org/releases/Aquamacs-Emacs-2.5.dmg'
  homepage 'http://aquamacs.org/'
  version '2.5'
  sha1 '2d9052b94751b0454e109700ff8d0204d80310f4'
  link 'Aquamacs.app'
end
```
assistant