http://blog.fiveruns.com/2008/3/3/compiling-ruby-rubygems-and-rails-on-ubuntu
rmagick 설치 : http://snippets.dzone.com/posts/show/4140
ImageMagick 설치 : http://www2.russbrooks.com:8080/2007/4/16/install-imagemagick-rmagick-on-ubuntu-kubuntu (Download : http://rmagick.rubyforge.org/install-linux.html)
우분투에서 openssl 사용에 문제가 있는 경우 : http://blog.fiveruns.com/2008/3/3/compiling-ruby-rubygems-and-rails-on-ubuntu