运行rails服务器后，Gemfile中出错

Question

我尝试运行rails s并且它给了我一个错误：There was an error in your Gemfile, and Bundler cannot continue。

这是Gemfile：

source 'https://rubygems.org'

gem 'rails', '3.2.3'
gem 'bootstrap-sass'
gem 'will_paginate'
gem 'bootstrap-will_paginate'
gem 'annotate'
gem 'pg'
gem 'faker'
gem 'omniauth-facebook'
gem 'fb_graph'
gem 'jquery-rails'
gem 'haml'
gem 'haml-rails', '= 0.3.4'
gem 'bcrypt-ruby', '~> 3.0.0'
gem 'thin'
gem 'google-analytics-rails'
gem 'nokogiri'
gem 'differ'
gem 'geocoder'
gem 'newrelic_rpm'

group :development do
  gem "rails-erd"
  gem 'rspec'
  gem 'quiet_assets'
end

group :test, :development do
  gem 'mail_safe', '0.3.1'
  gem "rspec-rails", "~> 2.0"
  gem 'shoulda-matchers'
  gem "factory_girl_rails", "~> 3.0"
  gem 'pry'
  gem 'pry-rails'
  gem 'pry-remote'
  gem 'pry-nav'
end

group :assets do
  gem 'sass-rails',   '~> 3.2.3'
  gem 'coffee-rails', '~> 3.2.1'
  gem 'uglifier', '>= 1.0.3'
end

group :development, :production do
  gem 'gmaps4rails'
end