net-ssh requires the following gems for ed25519 support

Mac OS使用capistrano进行部署输入bundle exec cap production deploy:check时候得到以下错误：
解决方式：

 ssh-add -K ~/.ssh/id_rsa

可以看到输出:

 => Identity added: /Users/xander/.ssh/id_rsa (xxxxxx@qq.com)

请注意你的pc~/.ssh/id_rsa 路径可能和我不同。

net-ssh requires the following gems for ed25519 support:

• ed25519 (>= 1.2, < 2.0)
• bcrypt_pbkdf (>= 1.0, < 2.0)
  See https://github.com/net-ssh/net-ssh/issues/565 for more information
  Gem::LoadError : "ed25519 is not part of the bundle. Add it to your Gemfile."
  (Backtrace restricted to imported tasks)
  cap aborted!
  NotImplementedError: OpenSSH keys only supported if ED25519 is available
  net-ssh requires the following gems for ed25519 support:
• ed25519 (>= 1.2, < 2.0)
• bcrypt_pbkdf (>= 1.0, < 2.0)
  See https://github.com/net-ssh/net-ssh/issues/565 for more information
  Gem::LoadError : "ed25519 is not part of the bundle. Add it to your Gemfile."

Tasks: TOP => rbenv:validate
(See full trace by running task with --trace)

参考：https://github.com/net-ssh/net-ssh/issues/478