warning: already initialized constant PDF
rails-3-upgrade, ruby-on-rails-3, rubygems, wicked-pdf
Solution
You might have this in your `config/initializers/mime_types.rb` file.
Mime::Type.register 'application/pdf', :pdf
It looks like newer versions of rails already registers it.
Problem
Right now I am working on rails 3.0.0. If I run my project in terminal, I get this warning. Please help me. /usr/share/ruby-rvm/gems/ruby-1.9.2-p290/gems/actionpack-3.0.0/lib/action_dispatch/http/mime_type.rb:98: warning: already initialized constant PDF