Getting Started and JRuby

When following the getting started guide with the JRuby tarball, after
the completion of step 4.3, the application will simply return an
error "ExecJS::RuntimeError" at line 6:
<%= javascript_include_tag "application" %>

This can be fixed by removing app/assets/javascripts/home.js.coffee

From what I have been able to google (
http://railscasts.com/episodes/265-rails-3-1-overview?view=comments#comment_153006
), rails is depending on the existence of a library to execute
javascript, but simply running "gem install therubyrhino" was not
fixing the error for me.

if I can suggest adding instructions on installing something like
therubyrhino or simply removing coffee files, it would save a lot of
time for a beginner.