ssh_options

allow user set ssh_options per server
user can provide global ssh settings

for example in deploy.rb:

      {
         keys: %w(/home/user/.ssh/id_rsa),
         forward_agent: false,
         auth_methods: %w(publickey password)
      }
show ssh options in template
Merge pull request #557 from korin/ssh-options

Allow SSHKit::Backend.ssh_options to be set.