ruby-on-rails-3 - Railties を使用して gem から rails 3 routes.rb にルートを挿入する (デバイスの問題)

Question

railtie を使用して、gem からホスト アプリへのルートを自動的に挿入したいと考えています。これまでのところ、次のようなものがあります。

module Fabes
  class FabesRailtie < ::Rails::Railtie
    ActionController::Base.send :include, Fabes::Helper
    ActionController::Base.helper Fabes::Helper

    initializer 'fabes.routes', after: :after_initialize do |app|
      app.routes.draw do
        match '/fabes' => Fabes::Admin, as: :fabes_admin
      end
    end
  end
end

これは機能しています (ホスト アプリから呼び出されています) が、/fabesルートにアクセスしようとしたり、単にルートを一覧表示しようとすると、devise エラーで失敗します:

fuzzyalej@fuzzyalej:~/code/fabes-rails-example (master *)$ rake routes --trace
** Invoke routes (first_time)
** Invoke environment (first_time)
** Execute environment
rake aborted!
undefined method `failure_app=' for nil:NilClass
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/devise-2.1.2/lib/devise.rb:406:in `configure_warden!'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/devise-2.1.2/lib/devise/rails/routes.rb:20:in `finalize_with_devise!'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/actionpack-3.2.6/lib/action_dispatch/routing/route_set.rb:261:in `draw'
/Users/fuzzyalej/code/fabes/lib/fabes/railtie.rb:7:in `block in <class:FabesRailtie>'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.6/lib/rails/initializable.rb:30:in `instance_exec'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.6/lib/rails/initializable.rb:30:in `run'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.6/lib/rails/initializable.rb:55:in `block in run_initializers'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.6/lib/rails/initializable.rb:54:in `each'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.6/lib/rails/initializable.rb:54:in `run_initializers'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.6/lib/rails/application.rb:136:in `initialize!'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.6/lib/rails/railtie/configurable.rb:30:in `method_missing'
/Users/fuzzyalej/code/fabes-rails-example/config/environment.rb:5:in `<top (required)>'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/activesupport-3.2.6/lib/active_support/dependencies.rb:251:in `require'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/activesupport-3.2.6/lib/active_support/dependencies.rb:251:in `block in require'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/activesupport-3.2.6/lib/active_support/dependencies.rb:236:in `load_dependency'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/activesupport-3.2.6/lib/active_support/dependencies.rb:251:in `require'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.6/lib/rails/application.rb:103:in `require_environment!'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/railties-3.2.6/lib/rails/application.rb:292:in `block (2 levels) in initialize_tasks'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `block in execute'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:176:in `block in invoke_prerequisites'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:174:in `each'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:174:in `invoke_prerequisites'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:157:in `block in invoke_with_call_chain'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/lib/ruby/gems/1.9.1/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/bin/rake:23:in `load'
/Users/fuzzyalej/.rbenv/versions/1.9.3-p194/bin/rake:23:in `<main>'
Tasks: TOP => routes => environment

このようにルートを直接注入できるかどうか、または代わりにジェネレーターを使用する必要があるかどうかはわかりません..

この問題について何か考えはありますか？