NameError: uninitialized constant Faker::

Question

Before(:all) do 
    puts "HELLO ALL :D"
end

I have some problem with my code:

/spec/factories.rb

require 'faker'
FactoryGirl.define do
    factory :booking_error do 
    booking_id       { Faker::Number.number(3).to_i }
    error_type_cd    BookingError.error_types.values.shuffle.first
    process_name     Enums::FlightEnum::PROCESSES.keys.shuffle.first
    description      "DESCRIPTION"
    old_value        "OLD_STRING"
    new_value        "NEW_STRING"
    end
end

/spec/models/booking_error_spec.rb

require 'spec_helper'
describe BookingError do
    before(:all) do
        @booking_error       = FactoryGirl.build(:booking_error)
        @booking_error_types = BookingError.error_types
    end

    it 'Validating BookingError save.' do
        @booking_error.save.should be_true
    end
end

Gemfile

source 'https://rubygems.org'

gem 'rails', '3.2.13'

gem 'mysql2'                , '0.3.11'
gem 'devise'                , '2.2.0.rc'
gem 'devise-encryptable'    , '0.1.1'
gem 'unicorn'               , '4.5.0'
gem 'kaminari'              , '0.14.1'
gem 'memcache-client'       , '1.8.5'
gem 'simple_enum'           , '1.6.4'
gem 'resque'                , '1.23.0'    , :require => "resque/server"
gem 'resque-logger'         , '0.1.0'
gem 'resque-workers-lock'
gem 'whenever'              , '0.8.1'     , :require => false
gem 'httparty'              , '0.9.0'
gem 'newrelic_rpm'          , '3.6.1.88'
gem 'cancan'                , '1.6.8'
gem 'rolify'                , '3.2.0'
gem 'json-schema'           , '1.1.1'
gem 'faker'                 , '1.1.2'
gem 'ruby-enum'             , '0.2.1'
gem 'mail'                  , '2.5.4'
gem 'daemons-rails'

group :develop, :test do
  gem 'capistrano'          , '2.13.5'
  gem 'capistrano-unicorn'  , '0.1.6'     , :require => false
  gem 'capistrano-resque'   , '~> 0.1.0'  , :require => false
  gem 'rvm-capistrano'      , '1.2.7'
  gem 'capistrano-ext'
  gem 'rspec-rails'         , '2.12.0'
  gem 'debugger'            , '1.5.0'
  gem 'thin'                , '1.5.0'
  gem 'annotate'            , '2.5.0'
  gem 'factory_girl_rails'  , '4.1.0'
  gem 'yard'                , '0.8.5.2'
end


# Gems used only for assets and not required
# in production environments by default.
group :assets do
  gem 'therubyracer'            , '0.10.2'
  gem 'coffee-rails'            , '3.2.2'
  gem 'uglifier'                , '1.3.0'
  gem 'twitter-bootstrap-rails' , '2.1.9'
  gem 'sass'                    , '3.2.4'
  gem 'jquery-ui-rails'         , '3.0.0'
  gem 'less-rails'              , '2.2.6'
end

gem 'jquery-rails'              , '2.1.4'

When i run:

$ rspec spec/models/booking_error_spec.rb

I get the error that is in the title:

NameError: uninitialized constant Faker::Number