Ruby on Rails and Nginx on a Gentoo Slice presumably at Slicehost

This is a script I found online that I wanted to keep that and the page was removed for some reason. I hope I can preserve it. Let me know how I can improve it!

# login as root before running this script
# edit the username to reflect your preferences.
# save the script to a file and run it like:
# > /bin/bash this_script &
# remember the ampersand on the end and it'll run until it's done even if you disconnect

username='whatever_you_like_to_login_with'

# this bit will require some user interaction
useradd -m $username
passwd $username

# from here on we're rollin'
echo 'ACCEPT_KEYWORDS=~amd64' >> /etc/make.conf
echo 'USE="gif imagemagick innodb jbig jpeg jpeg2k pdf perl png mysql python ruby sqlite3 ssl svg truetype unicode xml xpm pcre -php -wmf -tiff -lcms -postgres"' >> /etc/make.conf
emerge --sync
emerge sudo
echo "$username ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers
emerge -C ssmtp
emerge vim ruby rubygems nginx subversion dev-db/mysql postfix vixie-cron
gem install --include-dependencies --no-ri --no-rdoc rails mongrel mongrel_cluster tzinfo BlueCloth RedCloth mysql sqlite3-ruby rspec zentest capistrano nginx_config_generator
gem install --include-dependencies --no-ri --no-rdoc activeresource --source http://gems.rubyonrails.org
emerge --config =dev-db/mysql-5.0.44-r1
rc-config add mysql default
/etc/init.d/mysql start
rc-config add nginx default
/etc/init.d/nginx start
rc-config add postfix default
/etc/init.d/postfix start