M在打开应用程序.........时收到以下错误消息应用程序中出现错误，无法为您的页面提供服务。如果您是应用程序所有者，请检查日志以了解详细信息。您可以在Heroku CLI中使用以下命令来完成此操作Heroku日志——tail
这是日志…我在这里错过了什么?
2021-03-01T17:03:26.388992+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
2021-03-01T17:03:26.389017+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
2021-03-01T17:03:26.389040+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.2/lib/active_support/dependencies.rb:324:in `block in require'
2021-03-01T17:03:26.389066+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.2/lib/active_support/dependencies.rb:291:in `load_dependency'
2021-03-01T17:03:26.389089+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.2/lib/active_support/dependencies.rb:324:in `require'
2021-03-01T17:03:26.389113+00:00 app[web.1]: from bin/rails:9:in `<main>'
2021-03-01T17:03:26.491419+00:00 heroku[web.1]: Process exited with status 1
2021-03-01T17:03:26.561190+00:00 heroku[web.1]: State changed from starting to crashed
2021-03-01T17:03:26.566083+00:00 heroku[web.1]: State changed from crashed to starting
2021-03-01T17:03:40.426026+00:00 heroku[web.1]: Starting process with command `bin/rails server -p ${PORT:-5000} -e production`
2021-03-01T17:03:42.175927+00:00 app[api]: Starting process with command `rails db:migrate` by user vineet19.rawat@gmail.com
2021-03-01T17:03:50.395757+00:00 app[web.1]: => Booting Puma
2021-03-01T17:03:50.395777+00:00 app[web.1]: => Rails 6.0.3.2 application starting in production
2021-03-01T17:03:50.395778+00:00 app[web.1]: => Run `rails server --help` for more startup options
2021-03-01T17:03:52.776562+00:00 app[web.1]: Exiting
2021-03-01T17:03:52.776980+00:00 app[web.1]: /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/loader/callbacks.rb:17:in `on_file_autoloaded': expected file /app/app/controllers/example_user.rb to define constant ExampleUser, but didn't (Zeitwerk::NameError)
2021-03-01T17:03:52.777048+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/kernel.rb:28:in `block in require'
2021-03-01T17:03:52.777075+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/kernel.rb:27:in `tap'
2021-03-01T17:03:52.777102+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/kernel.rb:27:in `require'
2021-03-01T17:03:52.777126+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/loader.rb:392:in `const_get'
2021-03-01T17:03:52.777151+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/loader.rb:392:in `block (2 levels) in eager_load'
2021-03-01T17:03:52.777207+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/loader.rb:742:in `block in ls'
2021-03-01T17:03:52.777234+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/loader.rb:734:in `foreach'
2021-03-01T17:03:52.777259+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/loader.rb:734:in `ls'
2021-03-01T17:03:52.777282+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/loader.rb:387:in `block in eager_load'
2021-03-01T17:03:52.777303+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/loader.rb:376:in `synchronize'
2021-03-01T17:03:52.777327+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/loader.rb:376:in `eager_load'
2021-03-01T17:03:52.777387+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/loader.rb:494:in `each'
2021-03-01T17:03:52.777410+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/loader.rb:494:in `eager_load_all'
2021-03-01T17:03:52.777434+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/application/finisher.rb:122:in `block in <module:Finisher>'
2021-03-01T17:03:52.777459+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/initializable.rb:32:in `instance_exec'
2021-03-01T17:03:52.777484+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/initializable.rb:32:in `run'
2021-03-01T17:03:52.777507+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/initializable.rb:61:in `block in run_initializers'
2021-03-01T17:03:52.777574+00:00 app[web.1]: from /app/vendor/ruby-2.6.6/lib/ruby/2.6.0/tsort.rb:228:in `block in tsort_each'
2021-03-01T17:03:52.777598+00:00 app[web.1]: from /app/vendor/ruby-2.6.6/lib/ruby/2.6.0/tsort.rb:350:in `block (2 levels) in each_strongly_connected_component'
2021-03-01T17:03:52.777623+00:00 app[web.1]: from /app/vendor/ruby-2.6.6/lib/ruby/2.6.0/tsort.rb:431:in `each_strongly_connected_component_from'
2021-03-01T17:03:52.777646+00:00 app[web.1]: from /app/vendor/ruby-2.6.6/lib/ruby/2.6.0/tsort.rb:349:in `block in each_strongly_connected_component'
2021-03-01T17:03:52.777670+00:00 app[web.1]: from /app/vendor/ruby-2.6.6/lib/ruby/2.6.0/tsort.rb:347:in `each'
2021-03-01T17:03:52.777711+00:00 app[web.1]: from /app/vendor/ruby-2.6.6/lib/ruby/2.6.0/tsort.rb:347:in `call'
2021-03-01T17:03:52.777751+00:00 app[web.1]: from /app/vendor/ruby-2.6.6/lib/ruby/2.6.0/tsort.rb:347:in `each_strongly_connected_component'
2021-03-01T17:03:52.777773+00:00 app[web.1]: from /app/vendor/ruby-2.6.6/lib/ruby/2.6.0/tsort.rb:226:in `tsort_each'
2021-03-01T17:03:52.777798+00:00 app[web.1]: from /app/vendor/ruby-2.6.6/lib/ruby/2.6.0/tsort.rb:205:in `tsort_each'
2021-03-01T17:03:52.777821+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/initializable.rb:60:in `run_initializers'
2021-03-01T17:03:52.777845+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/application.rb:363:in `initialize!'
2021-03-01T17:03:52.777868+00:00 app[web.1]: from /app/config/environment.rb:5:in `<main>'
2021-03-01T17:03:52.777922+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
2021-03-01T17:03:52.777947+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
2021-03-01T17:03:52.777971+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
2021-03-01T17:03:52.777997+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
2021-03-01T17:03:52.778021+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
2021-03-01T17:03:52.778059+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/kernel.rb:34:in `require'
2021-03-01T17:03:52.778100+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.2/lib/active_support/dependencies.rb:324:in `block in require'
2021-03-01T17:03:52.778125+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.2/lib/active_support/dependencies.rb:291:in `load_dependency'
2021-03-01T17:03:52.778152+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.2/lib/active_support/dependencies.rb:324:in `require'
2021-03-01T17:03:52.778176+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:49:in `require_relative'
2021-03-01T17:03:52.778198+00:00 app[web.1]: from config.ru:3:in `block in <main>'
2021-03-01T17:03:52.778244+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/rack-2.2.3/lib/rack/builder.rb:116:in `eval'
2021-03-01T17:03:52.778282+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/rack-2.2.3/lib/rack/builder.rb:116:in `new_from_string'
2021-03-01T17:03:52.778308+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/rack-2.2.3/lib/rack/builder.rb:105:in `load_file'
2021-03-01T17:03:52.778331+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/rack-2.2.3/lib/rack/builder.rb:66:in `parse_file'
2021-03-01T17:03:52.778354+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/rack-2.2.3/lib/rack/server.rb:349:in `build_app_and_options_from_config'
2021-03-01T17:03:52.778400+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/rack-2.2.3/lib/rack/server.rb:249:in `app'
2021-03-01T17:03:52.778440+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/rack-2.2.3/lib/rack/server.rb:422:in `wrapped_app'
2021-03-01T17:03:52.778465+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/rack-2.2.3/lib/rack/server.rb:312:in `block in start'
2021-03-01T17:03:52.778489+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/rack-2.2.3/lib/rack/server.rb:379:in `handle_profiling'
2021-03-01T17:03:52.778513+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/rack-2.2.3/lib/rack/server.rb:311:in `start'
2021-03-01T17:03:52.778538+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/commands/server/server_command.rb:39:in `start'
2021-03-01T17:03:52.778576+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/commands/server/server_command.rb:147:in `block in perform'
2021-03-01T17:03:52.778615+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/commands/server/server_command.rb:138:in `tap'
2021-03-01T17:03:52.778640+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/commands/server/server_command.rb:138:in `perform'
2021-03-01T17:03:52.778664+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/thor-1.0.1/lib/thor/command.rb:27:in `run'
2021-03-01T17:03:52.778686+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/thor-1.0.1/lib/thor/invocation.rb:127:in `invoke_command'
2021-03-01T17:03:52.778710+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/thor-1.0.1/lib/thor.rb:392:in `dispatch'
2021-03-01T17:03:52.778752+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/command/base.rb:69:in `perform'
2021-03-01T17:03:52.778789+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/command.rb:46:in `invoke'
2021-03-01T17:03:52.778813+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/railties-6.0.3.2/lib/rails/commands.rb:18:in `<main>'
2021-03-01T17:03:52.778838+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
2021-03-01T17:03:52.778862+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
2021-03-01T17:03:52.778886+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
2021-03-01T17:03:52.778925+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
2021-03-01T17:03:52.778964+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
2021-03-01T17:03:52.778989+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.2/lib/active_support/dependencies.rb:324:in `block in require'
2021-03-01T17:03:52.779014+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.2/lib/active_support/dependencies.rb:291:in `load_dependency'
2021-03-01T17:03:52.779037+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.3.2/lib/active_support/dependencies.rb:324:in `require'
2021-03-01T17:03:52.779060+00:00 app[web.1]: from bin/rails:9:in `<main>'
2021-03-01T17:03:52.858760+00:00 heroku[web.1]: Process exited with status 1
2021-03-01T17:03:52.957145+00:00 heroku[web.1]: State changed from starting to crashed
2021-03-01T17:03:54.875119+00:00 heroku[run.3338]: State changed from starting to up
2021-03-01T17:03:54.983968+00:00 heroku[run.3338]: Awaiting client
2021-03-01T17:03:55.013747+00:00 heroku[run.3338]: Starting process with command `rails db:migrate`
2021-03-01T17:04:03.908104+00:00 heroku[run.3338]: Process exited with status 0
2021-03-01T17:04:03.956135+00:00 heroku[run.3338]: State changed from up to complete
2021-03-01T17:04:17.990487+00:00 app[api]: Starting process with command `rails db:seed` by user vineet19.rawat@gmail.com
2021-03-01T17:04:31.107131+00:00 heroku[run.7311]: State changed from starting to up
2021-03-01T17:04:31.517826+00:00 heroku[run.7311]: Awaiting client
2021-03-01T17:04:31.554963+00:00 heroku[run.7311]: Starting process with command `rails db:seed`
2021-03-01T17:06:22.786614+00:00 heroku[run.7311]: Process exited with status 0
2021-03-01T17:06:22.861553+00:00 heroku[run.7311]: State changed from up to complete
2021-03-01T17:09:19.967120+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=still-scrubland-60280.herokuapp.com request_id=d8dd773f-4e4d-4b93-9870-6dbc62b7de02 fwd="157.38.50.136" dyno= connect= service= status=503 bytes= protocol=https
2021-03-01T17:09:21.311235+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=still-scrubland-60280.herokuapp.com request_id=843f886d-790e-4e08-ba71-0a14f728b3f9 fwd="157.38.50.136" dyno= connect= service= status=503 bytes= protocol=https
当这种情况发生时，通常意味着你的代码中有一个bug，当遇到这个bug时，rails应用程序会崩溃。通常可以通过仔细阅读这些堆栈跟踪来发现错误。在您的例子中，这看起来像错误:2021-03-01T17:03:52.776980+00:00 app[web.1]: /app/vendor/bundle/ruby/2.6.0/gems/zeitwerk-2.4.0/lib/zeitwerk/loader/callbacks.rb:17:in on_file_autoloaded': expected file /app/app/controllers/example_user.rb to define constant ExampleUser, but didn't (Zeitwerk::NameError)