Рельсы не могут быть запущены Ошибка загрузки

Question

Я пытаюсь переустановить рельсы и удалить мой .rbenv и установить снова. Ни один из методов не работает. Я использую рельсы 4.2.1.

Вот ошибка, которую я получил, когда «рельсы запуска сервера»:

/Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:274:in `require': cannot load such file -- rack/handler/start (LoadError) 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:274:in `block in require' 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:240:in `load_dependency' 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/activesupport-4.2.1/lib/active_support/dependencies.rb:274:in `require' 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/rack-1.6.4/lib/rack/handler.rb:78:in `try_require' 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/rack-1.6.4/lib/rack/handler.rb:16:in `get' 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/rack-1.6.4/lib/rack/server.rb:290:in `server' 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/server.rb:125:in `print_boot_information' 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/server.rb:75:in `start' 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:80:in `block in server' 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:75:in `tap' 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:75:in `server' 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!' 
from /Users/CQ/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands.rb:17:in `<top (required)>' 
from bin/rails:8:in `require' 
from bin/rails:8:in `<main>' 

Answer 1

Команда только rails server или rails s.

http://guides.rubyonrails.org/command_line.html#rails-server