我设置
config.assets.initialize_on_precompile = false
在 application.rb 中。资产已通过 run 在本地成功预编译
RAILS_ENV=production bundle exec rake assets:precompile
当推送到 Heroku 时未检测到 manifest-fingerprint.json（Rails 4.0 生成 manifest.json 而不是 manifest.yml），Heroku 尝试再次运行预编译。然后我得到了错误：
Running: rake assets:precompile
rake aborted!
could not connect to server: Connection refused
Is the server running on host "127.0.0.1" and accepting
TCP/IP connections on port 5432?
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/postgresql_adapter.rb:771:in `initialize'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/postgresql_adapter.rb:771:in `new'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/postgresql_adapter.rb:771:in `connect'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/postgresql_adapter.rb:493:in `initialize'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/postgresql_adapter.rb:41:in `new'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/postgresql_adapter.rb:41:in `postgresql_connection'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/abstract/connection_pool.rb:446:in `new_connection'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/abstract/connection_pool.rb:456:in `checkout_new_connection'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/abstract/connection_pool.rb:427:in `acquire_connection'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/abstract/connection_pool.rb:364:in `block in checkout'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/abstract/connection_pool.rb:363:in `checkout'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/abstract/connection_pool.rb:273:in `block in connection'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/abstract/connection_pool.rb:272:in `connection'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_adapters/abstract/connection_pool.rb:552:in `retrieve_connection'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_handling.rb:79:in `retrieve_connection'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/connection_handling.rb:53:in `connection'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/model_schema.rb:208:in `columns'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/model_schema.rb:242:in `column_defaults'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/locking/optimistic.rb:169:in `column_defaults'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/core.rb:164:in `initialize'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/inheritance.rb:24:in `new'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activerecord-4.0.0.beta1/lib/active_record/inheritance.rb:24:in `new'
/tmp/build_2ospgf61r6sch/lib/student_module.rb:11:in `acts_as_student'
/tmp/build_2ospgf61r6sch/app/models/applicant.rb:4:in `<class:Applicant>'
/tmp/build_2ospgf61r6sch/app/models/applicant.rb:3:in `<top (required)>'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0.beta1/lib/active_support/dependencies.rb:228:in `require'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0.beta1/lib/active_support/dependencies.rb:228:in `block in require'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0.beta1/lib/active_support/dependencies.rb:213:in `load_dependency'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0.beta1/lib/active_support/dependencies.rb:228:in `require'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0.beta1/lib/active_support/dependencies.rb:329:in `require_or_load'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0.beta1/lib/active_support/dependencies.rb:288:in `depend_on'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0.beta1/lib/active_support/dependencies.rb:206:in `require_dependency'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/engine.rb:464:in `block (2 levels) in eager_load!'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/engine.rb:463:in `each'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/engine.rb:463:in `block in eager_load!'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/engine.rb:461:in `each'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/engine.rb:461:in `eager_load!'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/engine.rb:346:in `eager_load!'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/application/finisher.rb:56:in `each'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/application/finisher.rb:56:in `block in <module:Finisher>'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/initializable.rb:30:in `instance_exec'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/initializable.rb:30:in `run'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/initializable.rb:55:in `block in run_initializers'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/initializable.rb:54:in `run_initializers'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/application.rb:213:in `initialize!'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/railtie/configurable.rb:30:in `method_missing'
/tmp/build_2ospgf61r6sch/config/environment.rb:5:in `<top (required)>'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0.beta1/lib/active_support/dependencies.rb:228:in `require'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0.beta1/lib/active_support/dependencies.rb:228:in `block in require'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0.beta1/lib/active_support/dependencies.rb:213:in `load_dependency'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.0.beta1/lib/active_support/dependencies.rb:228:in `require'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/application.rb:187:in `require_environment!'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/railties-4.0.0.beta1/lib/rails/application.rb:247:in `block in run_tasks_blocks'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:246:in `call'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:246:in `block in execute'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:241:in `each'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:241:in `execute'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:184:in `block in invoke_with_call_chain'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:177:in `invoke_with_call_chain'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:170:in `invoke'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/sprockets-rails-2.0.0.rc4/lib/sprockets/rails/task.rb:16:in `block (2 levels) in define'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:246:in `call'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:246:in `block in execute'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:241:in `each'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:241:in `execute'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:184:in `block in invoke_with_call_chain'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:177:in `invoke_with_call_chain'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:205:in `block in invoke_prerequisites'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:203:in `each'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:203:in `invoke_prerequisites'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:183:in `block in invoke_with_call_chain'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:177:in `invoke_with_call_chain'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/task.rb:170:in `invoke'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/application.rb:143:in `invoke_task'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/application.rb:101:in `block (2 levels) in top_level'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/application.rb:101:in `each'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/application.rb:101:in `block in top_level'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/application.rb:110:in `run_with_threads'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/application.rb:95:in `top_level'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/application.rb:73:in `block in run'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/application.rb:160:in `standard_exception_handling'
/tmp/build_2ospgf61r6sch/vendor/bundle/ruby/2.0.0/gems/rake-10.0.4/lib/rake/application.rb:70:in `run'
似乎错误是由于 lib/student_module.rb 中的文件引起的，该文件在 config/initializers/student_init.rb 中是必需的：
#lib/student_module.rb, the error pointed to this line：
user_attributes = User.new.abttributes.keys
#config/initializers/student_init.rb
require 'student_module'
ActiveRecord::Base.extend Student
该错误可能是因为 Heroku 初始化了应用程序，其中包括与数据库的连接。但我不应该看到这样的消息
rake aborted!
could not connect to server: Connection refused
Is the server running on host "127.0.0.1" and accepting
TCP/IP connections on port 5432?
因为我将 config.assets.initialize_on_precompile 设置为 false 并在本地预编译资产。
有什么建议可以解决这个问题吗？谢谢！