cannot load such file — capistrano/setup (LoadError)

问题

I am following https://gorails.com/deploy/ubuntu/16.04

Initially i have one version of capistrano 3.8.1 and my problem initially is:

nicoara@ubuntu:~/deploy_test$ cap install STAGES=production
  /home/nicoara/.rbenv/versions/2.2.3/lib/ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require': cannot load such file -- capistrano/cli (LoadError)

i solve this with "gem install rvm-capistrano" which installs another version of capistrano as well, 2.15.6, and now the error is:

nicoara@ubuntu:~/deploy_test$ cap install STAGES=production:
`require': cannot load such file -- capistrano/setup (LoadError)

which is unsolvable to me at this point.

回答1:

As the comment states, there are a few steps to follow:

1. Make sure all capistrano/* gems are listed in your Gemfile.
2. Run bundle install to install them.
3. Make sure they're spelled correctly in your Capfile (I've messed that up more than once!).
4. Prepend cap commands with bundle exec to be extra safe, i.e. STAGES=production bundle exec cap install.

来源：https://stackoverflow.com/questions/43790085/cannot-load-such-file-capistrano-setup-loaderror