我已经在这几个小时了，我无法弄清楚我做错了什么。我正在使用Ruby 2.1.5，Rails 4.2.0，Ubuntu 14.04服务器（在digitalocean上），以及其余的我的gemfile：
...
gem 'unicorn'
gem 'capistrano', '~> 3.4.0'
gem 'capistrano-rails', group: :development
gem 'capistrano-passenger'
...
我按照这两个教程中的配置说明操作：tutorial 1和tutorial 2。
他们必须有点过时，因为视频中的capistrano并不是说它需要capistrano-passenger，但在我的机器上它确实如此。我试着跑步。
但是，教程中的所有内容都工作正常，除了最后一个语句，使用此命令bin/cap production deploy部署服务器。我收到一条错误
cap aborted!
SSHKit::Runner::ExecuteError: Exception while executing as deploy@0.0.0.0: cp exit status: 1
cp stdout: Nothing written
cp stderr: cp: cannot stat ‘/opt/www/myapp/releases/20150326054249/public/assets/manifest*’: No such file or directory
SSHKit::Command::Failed: cp exit status: 1
cp stdout: Nothing written
cp stderr: cp: cannot stat ‘/opt/www/myapp/releases/20150326054249/public/assets/manifest*’: No such file or directory
Tasks: TOP => deploy:assets:backup_manifest
(See full trace by running task with --trace)
The deploy has failed with an error: Exception while executing as deploy@0.0.0.0: cp exit status: 1
cp stdout: Nothing written
cp stderr: cp: cannot stat ‘/opt/www/myapp/releases/20150326054249/public/assets/manifest*’: No such file or directory
由于我看过其他有类似说明的教程，我觉得它没事，我只是缺少一些小东西。
此外，它失败后，它以某种方式卸载capistrano。因为如果我再次尝试运行它，我会收到此错误：
cap aborted!
LoadError: cannot load such file -- capistrano/rails
/home/jeremy/421_WEBAPP/myapp/Capfile:6:in `require'
/home/jeremy/421_WEBAPP/myapp/Capfile:6:in `<top (required)>'
(See full trace by running task with --trace)
有人请求帮助，我再也不能把头发拉出来了