# Config.gem vs require 'somegem' **URL:** \ **Category:** Rails\ **Created:** [September 16, 2008, 7:25am UTC](https://www.ruby-forum.com/t/config-gem-vs-require-somegem/148682 "2008-09-16T07:25:46Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![giorgio](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/cab0a1/32.png) [@giorgio](https://www.ruby-forum.com/u/giorgio)\ **Post date:** [September 16, 2008, 7:25am UTC](https://www.ruby-forum.com/t/config-gem-vs-require-somegem/148682/1 "2008-09-16T07:25:46Z")
I am very confused by the config.gem statement in 2.1 If I put config.gem ‘pdf-writer’ in my environment.rb I get the following error when I try to instanciate a PDF object in my controller with the statement pdf = PDF::Writer.new uninitialized constant CollectionsController::PDF so I try putting require ‘pdf/writer’ in my environment.rb and the application fails to load with: no such file to load – pdf-writer /usr/local/lib/site\_ruby/1.8/ rubygems/custom\_require.rb:27:in `gem_original_require' /usr/local/lib/ site_ruby/1.8/rubygems/custom_require.rb:27:in`require’ /usr/lib/ruby/ gems/1.8/gems/activesupport-2.1.0/lib/active\_support/dependencies.rb: 509:in `require’ etc … The gem is in my vendor directory. I would like to get to the bottom of this as I have had similar problems with gems in the past and I dont really understand whether I still need a ‘require’ when I have the ‘config.gem’ Cheers George ---
**Author:** ![giorgio](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/cab0a1/32.png) [@giorgio](https://www.ruby-forum.com/u/giorgio)\ **Post date:** [September 16, 2008, 6:55pm UTC](https://www.ruby-forum.com/t/config-gem-vs-require-somegem/148682/2 "2008-09-16T18:55:20Z")
Same problem for me. I have installed ‘rubyist-aasm’ for restful\_authentication, but when I insert config.gem ‘rubyist-aasm’, I get an error message.