ruby 2.0.0p576（2014-09-19修订版47628）[i686-linux] Rails 4.1.6
我刚刚运行了rails new projectname和bundle install，当我尝试启动WEBrick服务器时，它会向我抛出以下内容：
rails s
/home/giri/.rvm/gems/ruby-2.0.0-p576/gems/actionpack-4.1.6/lib/action_controller/metal/strong_parameters.rb:106: warning: already initialized constant ActionController::Parameters::NEVER_UNPERMITTED_PARAMS
/home/giri/.rvm/gems/ruby-2.0.0-p576/gems/actionpack-4.1.6/lib/action_controller/metal/strong_parameters.rb:106: warning: previous definition of NEVER_UNPERMITTED_PARAMS was here
/home/giri/.rvm/gems/ruby-2.0.0-p576/gems/actionpack-4.1.6/lib/action_controller/metal/strong_parameters.rb:106: warning: already initialized constant ActionController::Parameters::NEVER_UNPERMITTED_PARAMS
/home/giri/.rvm/gems/ruby-2.0.0-p576/gems/actionpack-4.1.6/lib/action_controller/metal/strong_parameters.rb:106: warning: previous definition of NEVER_UNPERMITTED_PARAMS was here
/home/giri/.rvm/gems/ruby-2.0.0-p576/gems/uglifier-3.0.0/lib/uglifier.rb:5:in `require': cannot load such file -- execjs (LoadError)
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/uglifier-3.0.0/lib/uglifier.rb:5:in `<top (required)>'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/bundler-1.12.0.rc/lib/bundler/runtime.rb:88:in `require'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/bundler-1.12.0.rc/lib/bundler/runtime.rb:88:in `block (2 levels) in require'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/bundler-1.12.0.rc/lib/bundler/runtime.rb:83:in `each'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/bundler-1.12.0.rc/lib/bundler/runtime.rb:83:in `block in require'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/bundler-1.12.0.rc/lib/bundler/runtime.rb:72:in `each'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/bundler-1.12.0.rc/lib/bundler/runtime.rb:72:in `require'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/bundler-1.12.0.rc/lib/bundler.rb:102:in `require'
from /home/giri/test123/config/application.rb:7:in `<top (required)>'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:79:in `require'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:79:in `block in server'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:76:in `tap'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:76:in `server'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/railties-4.1.6/lib/rails/commands/commands_tasks.rb:40:in `run_command!'
from /home/giri/.rvm/gems/ruby-2.0.0-p576/gems/railties-4.1.6/lib/rails/commands.rb:17:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
这是我的Gem文件和ruby 2.0
source 'https://rubygems.org'
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.1.6'
# Use sqlite3 as the database for Active Record
gem 'sqlite3'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 4.0.3'
# 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
# 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', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0', group: :doc
# Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
gem 'spring', group: :development
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'
# Use unicorn as the app server
# gem 'unicorn'
# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development
# Use debugger
gem 'execjs'
gem 'therubyracer', :platforms => :ruby