Update dependency to beta4

Rakefile

@@ -37,7 +37,7 @@ end
 
 desc 'Default: run tests for all supported versions of Rails'
 task :default do
-  %w(2.3.8 3.0.0.beta3).each do |version|
+  %w(2.3.8 3.0.0.beta4).each do |version|
     system("RAILS_VERSION=#{version} rake -s test;")
   end
 end

test/rails3_root/Gemfile

@@ -1,6 +1,6 @@
 source 'http://rubygems.org'
 
-gem 'rails', '3.0.0.beta3'
+gem 'rails', '3.0.0.beta4'
 
 # Bundle edge Rails instead:
 # gem 'rails', :git => 'git://github.com/rails/rails.git'