Debian Etch with backports

Add this line in sources.list to get rails > 1.8.5 in rails etch

deb http://www.backports.org/debian etch-backports main contrib non-free
# deb ftp://ftp.nz.debian.org/backports etch-backports main contrib non-free
apt-get install debian-backports-keyring
aptitude update

# some ruby stuff
aptitude install -t etch-backports ruby1.8-dev libmysqlclient15off libmysqlclient15-dev mysql-common mysql-client libmysql-ruby1.8

# some system utils/libs
aptitude install apt-utils build-essential mysql-server mysql-common mysql-client memcached libxslt1-dev libpcre3-dev zlib1g-dev unzip gzip mytop  openssl

aptitude install -t etch-backports libopenssl-ruby

# gems
gem install rails mongrel mongrel_cluster -y

check this step-by-step

Image magick linux howto – http://rmagick.rubyforge.org/install2-linux.html

aptitude install libmagick9-dev  imagemagick librmagick-ruby1.8 imagemagick librmagick-ruby-doc  libmagick9-dev ruby1.8-dev

# for version 1 of imagemagick we use this rmagick, else try it without the -v
gem install rmagick -v 1.15.12 

# lets test it
> irb
require 'rubygems'
require 'RMagick'
Magick::CenterGravity
puts Magick::Long_version

# or with 

ruby -rrubygems -e "require 'RMagick'; puts Magick::Long_version;" 

I love this tutorial on rubyinside