title: Ubuntu rails install fails on zlib
body: <p>I've just moved over to Ubuntu 8.10 as my dev box; it's my first serious foray into Linux as a daily-use OS, and I'm having a hard time getting Rails going.  I have followed a number of tutorials which all seem to work fine, but when I try and use gem install or gem update on anything, I get an error that looks like this:</p>
  
  <pre><code>/usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require': no such file to load -- zlib (LoadError)
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/spec_fetcher.rb:1
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/commands/update_command.rb:5
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/command_manager.rb:167:in `load_and_instantiate'
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/command_manager.rb:88:in `[]'
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/command_manager.rb:144:in `find_command'
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/command_manager.rb:131:in `process_args'
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/command_manager.rb:102:in `run'
  from /usr/local/lib/ruby/site_ruby/1.8/rubygems/gem_runner.rb:58:in `run'
  from /usr/local/bin/gem:21
  </code></pre>
  
  <p>I have (as recommended in the tutorials) installed zlib, zlib1g, and zlib1g-dev.  I've even found a few tutorials on this particular problem (all for flavors other than mine, however) but they didn't help.</p>
  
  <p>I'm on Ubuntu 8.10, ruby version  1.8.8dev gem version 1.3.2</p>
  
  <p>I've tried reinstalling ruby and gems each and separately, to no avail.</p>