Heroku で Rails 3.1 アプリを git push heroku master するとこんなエラーが出ることがあると思います。 -----> Preparing app for Rails asset pipeline Running: rake assets:precompile rake aborted! Failed to connect to a master node at localhost:27017 Tasks: TOP => environment (See full trace by running task with --trace) Precompiling assets failed, enabling runtime asset compilation Injecting rails31_enable_runtime_asset_compilati