Ruby on rails 如何解决'require'；：无法在heroku上加载这样的文件--bundler（LoadError）

当我在heroku上运行迁移时，它会给我一个错误

heroku run rake db:migrate
Running rake db:migrate on testing-app... up, run.9199
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- bundler (LoadError)
from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from /app/bin/spring:8:in `<top (required)>'
from /app/bin/rake:3:in `load'
from /app/bin/rake:3:in `<main>'

heroku运行rake数据库：迁移
正在测试应用程序上运行rake db:migrate。。。起来，跑吧
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:“require”中：无法加载这样的文件--bundler（LoadError）
from/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in'require'
from/app/bin/spring:8:in`'
from/app/bin/rake:3:在“加载”中
from/app/bin/rake:3:in`'

您是否首先在heroku上设置了数据库？当我运行heroku时，请运行rake db:create。它还显示相同的错误

heroku run rake db:setup

尝试此操作或检查任何发出此异常的gem