Volundr/prawn-rails — pull request #10 by asanghi (2011-12-26 15:56:36+00:00)
Title: Prevent warning about redefinition of Mime::Type

My app seems to complain about PDF being predefined somewhere already.

````ruby
...actionpack-3.2.0.rc1/lib/action_dispatch/http/mime_type.rb:101: warning: already initialized constant PDF
````

It may be prudent to check before registering alias.