jnicklas/carrierwave — pull request #949 by snoopie (2013-01-10 16:41:42+00:00)
Title: Allow setting file content type based on file content(using libmagic)

Currently the only way to set content type in carrierwave is using file extension(CarrierWave::MimeTypes).
There is a ruby-filemagic gem which offers ruby bindings to the libmagic library.
This commit adds libmagic-based processor which allows to detect file MIME type based on file content.