Oi Joviane,
tentei olhar mas ainda não consegui voce pode da uma olhada onde no que eu posso ta fazendo de errado, meu comando ficou assim
C:\Users\PLANET TECH\lojadecamisetas>rails server
=> Booting Puma
=> Rails 5.1.5 application starting in development
=> Run rails server -h
for more startup options
SIGUSR2 not implemented, signal based restart unavailable!
SIGUSR1 not implemented, signal based restart unavailable!
** SIGHUP not implemented, signal based logs reopening unavailable!
Puma starting in single mode...
Version 3.11.2 (ruby 2.3.3-p222), codename: Love Song
Min threads: 5, max threads: 5
Environment: development
* Listening on tcp://0.0.0.0:3000
Use Ctrl-C to stop
Started GET "/" for 127.0.0.1 at 2018-02-18 15:47:24 -0300
Processing by Rails::WelcomeController#index as HTML
Rendering C:/RailsInstaller/Ruby2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.1.5/lib/rails/templates/rails/welcome/index.html.erb
Rendered C:/RailsInstaller/Ruby2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.1.5/lib/rails/templates/rails/welcome/index.html.erb (7.6ms)
Completed 200 OK in 822ms (Views: 122.3ms)
não consegui subir ele