Capistrano deploy.rb with rbenv, unicorn and nginx.

deploy.rb

require 'bundler/setup'
server "some-ip", :web, :app, :db, primary: true

default_run_options[:pty] = true
ssh_options[:forward_agent] = true

set :application, "application-name"
set :repository,  "git@git"

set :user, "deploy" # As defined on your server
set :deploy_to, "/home/#{user}/app/#{application}" # Directory in which the deployment will take place
set :deploy_via, :remote_cache
set :use_sudo, true
set :assets_path, "#{deploy_to}/shared/app"

set :scm, "git"
set :branch, "master"

set :default_environment, {
  'PATH' => "/home/deploy/.rbenv/shims:/home/deploy/.rbenv/bin:$PATH"
}

namespace :deploy do
  task :preowner do
    run "mkdir -p #{release_path}/tmp/cache"
    run "mkdir -p #{release_path}/tmp/sessions"
    run "mkdir -p #{release_path}/tmp/sockets"
  end
  task :chowner do
    sudo "chown -R deploy:deploy #{deploy_to}/current/tmp/*"
  end
  task :start do
    sudo "/etc/init.d/unicorn start"
  end

  task :stop do
    sudo "/etc/init.d/unicorn stop"
  end

  task :restart do
    sudo '/bin/bash -c "/etc/init.d/unicorn reload"'
  end

end

after 'deploy:update_code', 'deploy:preowner'