Use Bundler for gem management (#5638).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@8904 e93f8b46-1217-0410-a6f0-8f06a7374b81

config/preinitializer.rb

@@ -0,0 +1,20 @@
+begin
+  require "rubygems"
+  require "bundler"
+rescue LoadError
+  $stderr.puts "Redmine requires Bundler. Please install it with `gem install bundler`."
+  exit 1
+end
+
+if Gem::Version.new(Bundler::VERSION) < Gem::Version.new("1.0.21")
+  $stderr.puts "Redmine requires Bundler 1.0.21 (you're using #{Bundler::VERSION}).\nPlease install a newer version with `gem install bundler`."
+  exit 1
+end
+
+begin
+  ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../Gemfile", __FILE__)
+  Bundler.setup
+rescue Bundler::GemNotFound
+  $stderr.puts "Some gems may need to be installed or updated. Please run `bundle install`."
+  exit 1
+end