Doorkeeper Installation: Uninitialized Permanent Error

I am trying to install Doorkeeper to install new rails (4.0.2). After adding gem to gemfile and installing it, I try to run

rails generate doorkeeper:install

and get the following error:

/Users/mam8cc/Projects/doorkeeper/config/application.rb:10:in `<module:Doorkeeper>': uninitialized constant Doorkeeper::Rails::Application (NameError)
    from /Users/mam8cc/Projects/doorkeeper/config/application.rb:9:in `<top (required)>'
    from /Users/mam8cc/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.2/lib/rails/commands.rb:43:in `require'
    from /Users/mam8cc/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.2/lib/rails/commands.rb:43:in `<top (required)>'
    from bin/rails:4:in `require'
    from bin/rails:4:in `<main>'

My applications .rb

require File.expand_path('../boot', __FILE__)

require 'rails/all'

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(:default, Rails.env)

module Doorkeeper
  class Application < Rails::Application
    # Settings in config/environments/* take precedence over those specified here.
    # Application configuration should go into files in config/initializers
    # -- all .rb files in that directory are automatically loaded.

    # Set Time.zone default to the specified zone and make Active Record auto-convert to this zone.
    # Run "rake -D time" for a list of tasks for finding time zone names. Default is UTC.
    # config.time_zone = 'Central Time (US & Canada)'

    # The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded.
    # config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s]
    # config.i18n.default_locale = :de
  end
end

And my gemfile for posterity

source 'https://rubygems.org'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.0.2'

# Use sqlite3 as the database for Active Record
gem 'sqlite3'

# Use SCSS for stylesheets
gem 'sass-rails', '~> 4.0.0'

# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'

# Use CoffeeScript for .js.coffee assets and views
gem 'coffee-rails', '~> 4.0.0'

# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby
gem 'doorkeeper'

# Use jquery as the JavaScript library
gem 'jquery-rails'

# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'

# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 1.2'

group :doc do
  # bundle exec rake doc:rails generates the API under doc/api.
  gem 'sdoc', require: false
end

# Use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.1.2'

# Use unicorn as the app server
# gem 'unicorn'

# Use Capistrano for deployment
# gem 'capistrano', group: :development

# Use debugger
# gem 'debugger', group: [:development, :test]