我是rails的新手，所以我真的不知道如何诊断这个问题。我正在努力使用workling来完成一些后台任务，但是我遇到了一个问题。当我在我的Gemfile中包含workling gem然后运行“bundle install”。运行“rails s”时出现以下错误。谷歌这个错误确实提到更新宝石，但是我今天早上使用rvm安装了ruby和gem，所以我怀疑这是问题。
的Gemfile：
gem 'workling', '~> 0.4.9.9'
错误：
$ rails s
/home/usr1/.rvm/gems/ruby-1.9.3-p429/gems/workling-0.4.9.9/lib/workling.rb:16:in `<class:Hash>': uninitialized constant ActiveSupport::CoreExtensions (NameError)
from /home/usr1/.rvm/gems/ruby-1.9.3-p429/gems/workling-0.4.9.9/lib/workling.rb:15:in `<top (required)>'
from /home/usr1/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `require'
from /home/usr1/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
from /home/usr1/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `each'
from /home/usr1/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `block in require'
from /home/usr1/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `each'
from /home/usr1/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `require'
from /home/usr1/.rvm/gems/ruby-1.9.3-p429@global/gems/bundler-1.3.5/lib/bundler.rb:132:in `require'
from /home/usr1/rock/config/application.rb:7:in `<top (required)>'
from /home/usr1/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.13/lib/rails/commands.rb:53:in `require'
from /home/usr1/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.13/lib/rails/commands.rb:53:in `block in <top (required)>'
from /home/usr1/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.13/lib/rails/commands.rb:50:in `tap'
from /home/usr1/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.13/lib/rails/commands.rb:50:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'