I installed Ruby, RubyGems, Rails, and MySQL on Tiger (Mac OS-X 10.4).

All went well in Patrick Lenz' book on Rails, until the following error
surfaced when I attempted to open a ruby console from the shovell
directory within my home directory:

MyComputer:~/shovell myname$ ruby script/console
Loading development environment.
/usr/lib/ruby/1.8/irb/completion.rb:10:in `require': No such file to load -- readline (LoadError)
from /usr/lib/ruby/1.8/irb/completion.rb:10
from /usr/lib/ruby/1.8/irb/init.rb:218:in `require'
from /usr/lib/ruby/1.8/irb/init.rb:218:in `load_modules'
from /usr/lib/ruby/1.8/irb/init.rb:216:in `each'
from /usr/lib/ruby/1.8/irb/init.rb:216:in `load_modules'
from /usr/lib/ruby/1.8/irb/init.rb:21:in `setup'
from /usr/lib/ruby/1.8/irb.rb:54:in `start'
from /usr/bin/irb:13

Any fixes suggested, since I'm not at all experienced at reading and
debugging using these kinds of Ruby error messages?

Regards,
Ambulance_driver