我作为 heroku 指南进行部署。
但是当我使用推荐“heroku rake db:migrate”时，会出现以下错误：
Running rake db:migrate attached to terminal... up, run.1
(in /app)
rake aborted!
no such file to load -- test/unit/error
<internal:lib/rubygems/custom_require>:29:in `require'
<internal:lib/rubygems/custom_require>:29:in `require'
/app/.gems/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block in require'
/app/.gems/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in `new_constants_in'
/app/.gems/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `require'
/app/.gems/gems/activesupport-2.2.2/lib/active_support/deprecation.rb:224:in `<top (required)>'
<internal:lib/rubygems/custom_require>:29:in `require'
<internal:lib/rubygems/custom_require>:29:in `require'
/app/.gems/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block in require'
/app/.gems/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in `new_constants_in'
/app/.gems/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `require'
/app/.gems/gems/activesupport-2.2.2/lib/active_support.rb:37:in `<top (required)>'
<internal:lib/rubygems/custom_require>:29:in `require'
<internal:lib/rubygems/custom_require>:29:in `require'
/app/.gems/gems/rails-2.2.2/lib/tasks/misc.rake:11:in `<top (required)>'
/app/.gems/gems/rails-2.2.2/lib/tasks/rails.rb:4:in `load'
/app/.gems/gems/rails-2.2.2/lib/tasks/rails.rb:4:in `block in <top (required)>'
/app/.gems/gems/rails-2.2.2/lib/tasks/rails.rb:4:in `each'
/app/.gems/gems/rails-2.2.2/lib/tasks/rails.rb:4:in `<top (required)>'
<internal:lib/rubygems/custom_require>:29:in `require'
<internal:lib/rubygems/custom_require>:29:in `require'
/app/Rakefile:10:in `<top (required)>'
/usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:2373:in `load'
/usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:2373:in `raw_load_rakefile'
/usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:2007:in `block in load_rakefile'
/usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:2058:in `standard_exception_handling'
/usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:2006:in `load_rakefile'
/usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:1991:in `run'
/usr/ruby1.9.2/bin/rake:31:in `<main>'
jason@jason-VirtualBox:~/work/depot$ rake db:migrate
(in /home/jason/work/depot)
我在heroku中访问我的应用程序，它出现了错误：
应用程序错误
应用程序发生错误，无法提供您的页面。请稍后重试。如果您是应用程序所有者，请查看您的日志以获取详细信息。