耙db：migrate问题

如何解决耙db：migrate问题

| 在本地运行rake db：create或rake db：migrate时，我的应用程序按预期成功构建了表。但是，当在heroku上运行时（例如heroku rake db：migrate --trace --app），它突然给我以下错误：

C:\\>heroku rake db:migrate --trace --app foo rake aborted!
undefined method `task\' for #<Foo::Application:0x7f8e77aa1420>
/app/.bundle/gems/ruby/1.8/gems/railties-3.0.4/lib/rails/application.rb:214:in `initialize_tasks\'
/app/.bundle/gems/ruby/1.8/gems/railties-3.0.4/lib/rails/application.rb:139:in `load_tasks\'
/app/.bundle/gems/ruby/1.8/gems/railties-3.0.4/lib/rails/application.rb:77:in `send\'
/app/.bundle/gems/ruby/1.8/gems/railties-3.0.4/lib/rails/application.rb:77:in `method_missing\'
/app/Rakefile:7
/app/.bundle/gems/ruby/1.8/gems/rake-0.9.0/lib/rake/rake_module.rb:25:in `load\'
/app/.bundle/gems/ruby/1.8/gems/rake-0.9.0/lib/rake/rake_module.rb:25:in `load_rakefile\'
/app/.bundle/gems/ruby/1.8/gems/rake-0.9.0/lib/rake/application.rb:495:in `raw_load_rakefile\'
/app/.bundle/gems/ruby/1.8/gems/rake-0.9.0/lib/rake/application.rb:78:in `load_rakefile\'
/app/.bundle/gems/ruby/1.8/gems/rake-0.9.0/lib/rake/application.rb:129:in `standard_exception_handling\'
/app/.bundle/gems/ruby/1.8/gems/rake-0.9.0/lib/rake/application.rb:77:in `load_rakefile\'
/app/.bundle/gems/ruby/1.8/gems/rake-0.9.0/lib/rake/application.rb:61:in `run\'
/app/.bundle/gems/ruby/1.8/gems/rake-0.9.0/lib/rake/application.rb:129:in `standard_exception_handling\'
/app/.bundle/gems/ruby/1.8/gems/rake-0.9.0/lib/rake/application.rb:59:in `run\'
/app/.bundle/gems/ruby/1.8/gems/rake-0.9.0/bin/rake:31
/usr/ruby1.8.7/bin/rake:19:in `load\'
/usr/ruby1.8.7/bin/rake:19

查看Rakefile，这就是全部内容：

require File.expand_path(\'../config/application\',__FILE__)
require \'rake\'

Foo::Application.load_tasks

load_tasks行是第7行。我真的不确定更改了什么，但是肯定有所更改。有没有人遇到过此错误的经验？     

解决方法

看到那个 Rake 0.9.0存在一个问题。现在在您的Gemfile中使用0.8.7。