引入以下Gem

# /Gemfile
group :development do
   ...
  gem 'capistrano'
  gem 'capistrano-rails'
  gem 'capistrano3-puma'
  gem 'capistrano-rvm',     require: false
  gem 'capistrano-bundler'
  # gem 'capistrano-sidekiq'
end

运行以下命令

$ bundle exec cap install

编辑/Capfile文件

# Load DSL and set up stages
require "capistrano/setup"

# Include default deployment tasks
require "capistrano/deploy"

require "capistrano/scm/git"
install_plugin Capistrano::SCM::Git

# 引入Gemfile所引入的gems的任务
require "capistrano/rvm"
require "capistrano/bundler"
require "capistrano/rails/assets"
require "capistrano/rails/migrations"
require 'capistrano/puma'
install_plugin Capistrano::Puma

# Load custom tasks from `lib/capistrano/tasks` if you have any defined
Dir.glob("lib/capistrano/tasks/*.rake").each { |r| import r }

编辑/config/deploy.rb

# config valid for current version and patch releases of Capistrano
lock "~> 3.10.1"
set :rails_env, fetch(:stage)

# 修改应用名称，git仓库地址
set :application, "your_app_name"
set :repo_url, "your_repo_url"

# Default branch is :master
# ask :branch, `git rev-parse --abbrev-ref HEAD`.chomp

set :deploy_to, "/var/projects/#{fetch(:application)}_#{fetch(:rails_env)}"
set :rvm_ruby_version, 'ruby-2.3.0'
set :rvm_binary, '/usr/local/rvm/bin/rvm'

append :linked_dirs, 'tmp/pids', 'tmp/cache', 'log', 'public/uploads'

set :keep_releases, 5
set :keep_assets, 2

set :puma_bind,       "unix://#{shared_path}/tmp/pids/puma.sock"
set :puma_state,      "#{shared_path}/tmp/pids/puma.state"
set :puma_pid,        "#{shared_path}/tmp/pids/puma.pid"
set :puma_access_log, "#{release_path}/log/puma.error.log"
set :puma_error_log,  "#{release_path}/log/puma.access.log"
set :puma_preload_app, true
set :puma_worker_timeout, nil
set :puma_tag, "#{fetch(:application)}_#{fetch(:rails_env)}"
set :puma_init_active_record, true  # Change to false when not using ActiveRecord
set :puma_threads, [0, 5]
set :puma_workers, 1
set :puma_env, fetch(:rack_env, fetch(:rails_env))

namespace :deploy do

  desc 'Initial Deploy'
  task :initial do
    on roles(:app) do
      before 'deploy:restart', 'puma:start'
      invoke 'deploy'
    end
  end

  desc 'Restart application'
  task :restart do
    on roles(:app), in: :sequence, wait: 3 do
      invoke 'puma:restart'
    end
  end

  after  :finishing, :cleanup

end

编辑/config/deploy/staging.rb，编辑你要部署的环境，设置IP地址，用户名

server 'xx.xx.xx.xx', user: 'deploy', roles: %w{app db web}