heroku rails 3 application fails to start

After I've successfully deployed a Rails 3 app on heroku, it fails to start. The error log starts with:

/usr/ruby1.8.7/lib/ruby/gems/1.8/gems/bundler-0.9.26/lib/bundler/definition.rb:25:in from_lock': You changed yo开发者_如何学Cur Gemfile after locking. Please relock usingbundle lock` (Bundler::GemfileChanged)

I'm using bundler 1.0.7 on the development machine, but it looks like heroku's version is too old. Does anyone have a workaround?

Do this:

bundle lock
bundle install
bundle check <-- Optional, Just to check if everything worked fine.
bundle pack
bundle lock

It should work fine.

It appears the problem was actually caused by the devise_openid_authenticatable gem, which I was using it unpacked in the vendor/gems directory. I'm not sure why, though - probably because this gem packs a Gemfile in its root directory, too.