config/deploy/production.rb

set :stage, :production
server 'SERVER-IP', user: 'USERNAME', roles: %w{app}#, my_property: :my_value

server 'SERVER-IP',
   user: 'USERNAME',
   roles: %w{app},
   ssh_options: {
     user: 'USERNAME', # overrides user setting above
     forward_agent: false,
     auth_methods: %w(publickey password),
     password: 'PASSWORD'
   }