Do you have a detailed guide for this? Thanks a lot :)
in Windows:
gem install rmagick --source http://rubyforge.org/frs/download.php/61207/rmagick-2.11.0.gem
but according to this Installation Faq you need to install ImageMagick and GraphicsMagick first
you might also want to consult Seamless Support for MinGW and open-discussion and the notes of Akita on Rails on the One-Click Ruby Installer by Luis Lavena
UPDATE: here's an update on Akita on Rails' article