Ruby on Rails - rake db：migrate产生错误：“Rake Aborted！未初始化的常量Bundler”

我是一个全新的Ruby & Rails程序员。当我尝试首次运行rake：Ruby on Rails - rake db：migrate产生错误：“Rake Aborted！未初始化的常量Bundler”

$ rake db:migrate

我得到这个错误：

Rake Aborted! 
Uninitialized constant Bundler

放眼望去这里& google搜索，我不知道该怎么办。其中一个类似问题的“答案”是：“哦，看，ruby & rake安装在不同的bin目录中，这就是问题所在。” - 对我来说这是真的，但是解决方案是什么？我如何在正确的地方重新安装耙子？ &会解决我的问题吗？

$ which ruby 
/usr/local/bin/ruby 

$ which rake 
/usr/bin/rake 

$ rake db:migrate --trace 
(in /Users/jessephillips/src/rails_projects/demo_app) 
rake aborted! 
Could not find RubyGem bundler (>= 0) 
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems.rb:827:in `report_activate_error' 
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems.rb:261:in `activate' 
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems.rb:68:in `gem' 
/Users/jessephillips/src/rails_projects/demo_app/config/boot.rb:2 
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' 
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' 
/Users/jessephillips/src/rails_projects/demo_app/config/application.rb:1 
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' 
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' 
/Users/jessephillips/src/rails_projects/demo_app/Rakefile:4 
/Users/jessephillips/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2383:in `load' 
/Users/jessephillips/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2383:in `raw_load_rakefile' 
/Users/jessephillips/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2017:in `load_rakefile' 
/Users/jessephillips/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' 
/Users/jessephillips/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2016:in `load_rakefile' 
/Users/jessephillips/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2000:in `run' 
/Users/jessephillips/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' 
/Users/jessephillips/.gem/ruby/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run' 
/Users/jessephillips/.gem/ruby/1.8/gems/rake-0.8.7/bin/rake:31 
/usr/bin/rake:19:in `load' 
/usr/bin/rake:19

来源

2011-04-09 Jesse Phillips