我在 Nitrous.io 上做一个月 Rails 的教程。有一次，我的树上出现了一些奇怪的文件，我删除了它们。一切都停止了工作。
我跑了：
$ git add .
$ git checkout -f
并恢复了树。
但是，当我跑的时候：
$ rails server
我得到：
action@first-project-48185:~/pinteresting$ rails server
-bash: rails: command not found
我也试过：
$ ruby -v #and got an older version, so I reinstalled it
$ rails -v
action@first-project-48185:~/pinteresting$ rails -v
-bash: rails: command not found
当我运行时：
$ ruby -v #on MAC terminal, I get the correct version
$ rails -v #on MAC terminal, I get the correct version
有趣的是，当我运行时：
$ rails server or $ rails server -p 4000
我得到：
Franciscos-MacBook-Pro:pinteresting franciscomello$ rails server
/Library/Ruby/Gems/2.0.0/gems/sqlite3-1.3.8/lib/sqlite3.rb:6:in `require': cannot load such file -- sqlite3/sqlite3_native (LoadError)
以及下面的一堆其他文字：
from /Library/Ruby/Gems/2.0.0/gems/sqlite3-1.3.8/lib/sqlite3.rb:6:in `rescue in <top (required)>'
from /Library/Ruby/Gems/2.0.0/gems/sqlite3-1.3.8/lib/sqlite3.rb:2:in `<top (required)>'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `require'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `each'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `block in require'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `each'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `require'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler.rb:132:in `require'
from /Users/franciscomello/Desktop/pinteresting/config/application.rb:7:in `<top (required)>'
from /Library/Ruby/Gems/2.0.0/gems/railties-4.0.0/lib/rails/commands.rb:76:in `require'
from /Library/Ruby/Gems/2.0.0/gems/railties-4.0.0/lib/rails/commands.rb:76:in `block in <top (required)>'
from /Library/Ruby/Gems/2.0.0/gems/railties-4.0.0/lib/rails/commands.rb:73:in `tap'
from /Library/Ruby/Gems/2.0.0/gems/railties-4.0.0/lib/rails/commands.rb:73:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
Franciscos-MacBook-Pro:pinteresting franciscomello$ rails server -p 4000
/Library/Ruby/Gems/2.0.0/gems/sqlite3-1.3.8/lib/sqlite3.rb:6:in `require': cannot load such file -- sqlite3/sqlite3_native (LoadError)
from /Library/Ruby/Gems/2.0.0/gems/sqlite3-1.3.8/lib/sqlite3.rb:6:in `rescue in <top (required)>'
from /Library/Ruby/Gems/2.0.0/gems/sqlite3-1.3.8/lib/sqlite3.rb:2:in `<top (required)>'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `require'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `each'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `block in require'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `each'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `require'
from /Library/Ruby/Gems/2.0.0/gems/bundler-1.3.5/lib/bundler.rb:132:in `require'
from /Users/franciscomello/Desktop/pinteresting/config/application.rb:7:in `<top (required)>'
from /Library/Ruby/Gems/2.0.0/gems/railties-4.0.0/lib/rails/commands.rb:76:in `require'
from /Library/Ruby/Gems/2.0.0/gems/railties-4.0.0/lib/rails/commands.rb:76:in `block in <top (required)>'
from /Library/Ruby/Gems/2.0.0/gems/railties-4.0.0/lib/rails/commands.rb:73:in `tap'
from /Library/Ruby/Gems/2.0.0/gems/railties-4.0.0/lib/rails/commands.rb:73:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
令人沮丧的是，我一直处于最大的连胜纪录，没有任何错误或错误:(
有任何想法吗？