http://www.redmine.org/wiki/redmine/RedmineInstall
sudo aptitude install  ruby ruby1.8-dev libzlib-ruby rdoc irb rubygems mysql-server libmysql-ruby1.8 subversion librmagick-ruby
sudo vi /usr/bin/gem
require ‘rubygems’
require ‘rubygems/gem_runner’
Gem.manage_gems
sudo gem update –system
sudo gem install rails -v=2.1.2
mysql -u root -p -e “create database redmine character set utf8;”
mysql -u root -p -e “grant all privileges on redmine.* to ‘redmine’@'localhost’”
mysql -u root -p -e “set password for ‘redmine’@'localhost’ = password(’letmein’)”
cp config/database.yml.example config/database.yml
vi config/database.yml
rake db:migrate [...]