Installing Rails 3 in Ubuntu 10.4

For the record, and for those of my friends who are going to participate in the Rails Rumble next weekend: here's how you install Rails 3 on your Ubuntu Karmic system. (10.10, known as Maverick, is supposed to arrive tomorrow and might make this post obsolete. But I won't be risking an upgrade before the weekend.)

1. Install Ruby; apt contains the required version:

   sudo apt-get install ruby

2. Uninstall RubyGems, because we'll install a more recent version from source:

   sudo apt-get remove rubygems

3. Install RubyGems from source:
   

   cd /tmp
   wget http://production.cf.rubygems.org/rubygems/rubygems-1.3.7.tgz
   tar xzf rubygems-1.3.7.tgz
   cd rubygems-1.3.7
   sudo ruby setup.rb
   sudo ln -s gem1.8 /usr/bin/gem

4. Install Rails:

   sudo gem install rails