DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support will be removed in Rails 4.0

Question

Possible Duplicate:
Rails 2.3-style plugins and deprecation warnings running task in Heroku

I am running rake db:migrate gives me the following warnings and then aborts:

$ heroku rake db:migration --trace
DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support forthese plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from <top (required)> at /app/Rakefile:7)
DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from <top (required)> at /app/Rakefile:7)
DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from <top (required)> at /app/Rakefile:7)
rake aborted!
Don't know how to build task 'db:migration'
/app/.bundle/gems/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/task_manager.rb:49:in `[]'
/app/.bundle/gems/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:115:in`invoke_task'
/app/.bundle/gems/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level'
/app/.bundle/gems/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each'
/app/.bundle/gems/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level'
/app/.bundle/gems/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/app/.bundle/gems/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level'
/app/.bundle/gems/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run'
/app/.bundle/gems/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/app/.bundle/gems/ruby/1.9.1/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
/app/.bundle/gems/ruby/1.9.1/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
/app/.bundle/gems/ruby/1.9.1/bin/rake:19:in `load'
/app/.bundle/gems/ruby/1.9.1/bin/rake:19:in `<main>'

when I checked vendor/plugins folder I only found a file called .gitkeep and is empty

Answer 1

As an FYI in case people arrive here from search engines due to the question title. The deprecation warning is caused by Heroku injecting plugins - see Jared Beck's answer on this question: Rails 2.3-style plugins and deprecation warnings running task in Heroku

The solution proposed by nzifab above is valid for the underlying issue but this wasn't what was raised in the question title