rails server
=> Загрузка Puma
=> Приложение Rails 5.2.0, запускаемое в разработке
=> Запуск rails server -h
для дополнительных параметров запуска
[44266] Puma starting in cluster mode...
[44266] * Version 3.6.2 (ruby 2.5.1-p57), codename: Sleepy Sunday Serenity
[44266] * Min threads: 5, max threads: 5
[44266] * Environment: development
[44266] * Process workers: 1
[44266] * Preloading application
[44266] * Listening on tcp://localhost:3000
[44266] Use Ctrl-C to stop
[44266] - Worker 0 (pid: 44286) booted, phase: 0
^C[44266] - Gracefully shutting down workers...
[44266] === puma shutdown: 2018-06-12 14:28:53 -0500 ===
[44266] - Goodbye!
Exiting
пошел http://www.localhost3000.org/
говорит, что вы забыли запустить свой сервер
Running
Rails 5.2.0
Postgesql 9.6