using bundler

Gemfile

@@ -0,0 +1,4 @@
+disable_system_gems
+bundle_path "vendor/bundler_gems"
+
+gem 'rails', '2.3.5'

config/boot.rb

@@ -36,8 +36,19 @@ def preinitializer_path
   class Boot
     def run
       load_initializer
+      extend_environment
       Rails::Initializer.run(:set_load_path)
     end
+
+    def extend_environment
+      Rails::Initializer.class_eval do
+        old_load = instance_method(:load_environment)
+        define_method(:load_environment) do
+          Bundler.require_env RAILS_ENV
+          old_load.bind(self).call
+        end
+      end
+    end
   end
 
   class VendorBoot < Boot

config/preinitializer.rb

@@ -0,0 +1 @@
+require "#{File.dirname(__FILE__)}/../vendor/bundler_gems/environment"