Got this error when I try to run rake db:migrate. This error is about pdf generator plugin PLATFORM. I read on stackoverflow about and found this:

if Platform.is_windows?
include Win32PdfRenderer
elsif Platform.is_linux?
include NixPdfRenderer
else
raise "Unable to find Platform"
end

Once I'm on MAC , I have to comment the raise line. Do you know if there are others workaround to this? What should I do to make this work well on Mac?