I got NoMethodError for Tempfile in create_tempfile method in Rack::Thumb.

Apparently Tempfile#tap is not defined in my version of Ruby:

ruby 1.8.6 (2008-08-11 patchlevel 287) [universal-darwin9.0]

I fixed it by defining it myself:

if !Tempfile.public_methods.include?('tap')
  class Tempfile
    def tap
      yield self
      self
    end
  end
end

Probably this tiny fix doesn't justify a pull request?