如何在使用瘦Web服务器运行时避免不必要的路由错误。 有时会发生此错误，此路由不是我们使用的
logActionController::RoutingError (No route matches [GET] "/robots.txt"):
actionpack (3.2.19) lib/action_dispatch/middleware/debug_exceptions.rb:21:in `call'
actionpack (3.2.19) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
railties (3.2.19) lib/rails/rack/logger.rb:32:in `call_app'
railties (3.2.19) lib/rails/rack/logger.rb:16:in `block in call'
activesupport (3.2.19) lib/active_support/tagged_logging.rb:22:in `tagged'
railties (3.2.19) lib/rails/rack/logger.rb:16:in `call'
actionpack (3.2.19) lib/action_dispatch/middleware/request_id.rb:22:in `call'
rack (1.4.5) lib/rack/methodoverride.rb:21:in `call'
rack (1.4.5) lib/rack/runtime.rb:17:in `call'
activesupport (3.2.19) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.5) lib/rack/lock.rb:15:in `call'
actionpack (3.2.19) lib/action_dispatch/middleware/static.rb:63:in `call'
rack-cache (1.2) lib/rack/cache/context.rb:136:in `forward'
rack-cache (1.2) lib/rack/cache/context.rb:245:in `fetch'
rack-cache (1.2) lib/rack/cache/context.rb:185:in `lookup'
rack-cache (1.2) lib/rack/cache/context.rb:66:in `call!'
rack-cache (1.2) lib/rack/cache/context.rb:51:in `call'
airbrake (4.1.0) lib/airbrake/user_informer.rb:16:in `_call'
airbrake (4.1.0) lib/airbrake/user_informer.rb:12:in `call'
railties (3.2.19) lib/rails/engine.rb:484:in `call'
railties (3.2.19) lib/rails/application.rb:231:in `call'
railties (3.2.19) lib/rails/railtie/configurable.rb:30:in `method_missing'
thin (1.6.3) lib/thin/connection.rb:86:in `block in pre_process'
thin (1.6.3) lib/thin/connection.rb:84:in `catch'
thin (1.6.3) lib/thin/connection.rb:84:in `pre_process'
thin (1.6.3) lib/thin/connection.rb:53:in `process'
thin (1.6.3) lib/thin/connection.rb:39:in `receive_data'
eventmachine (1.0.3) lib/eventmachine.rb:187:in `run_machine'