Capistrano v3 configuration example

Capfile

# ...

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

config---deploy---production.rb

# Simple Role Syntax
# ==================
# Supports bulk-adding hosts to roles, the primary server in each group
# is considered to be the first unless any hosts have the primary
# property set.  Don't declare `role :all`, it's a meta role.

role :app, %w{root@my-project.com}
role :web, %w{root@my-project.com}
role :db,  %w{root@my-project.com}

server 'my-project.com', user: 'root', roles: %w{web app}

config---deploy.rb

lock '3.2.1'

set :application, 'project_name'
set :repo_url,    'git@example.com/repo.git'
set :deploy_to,   '/var/www/project_name'

set :linked_files, %w{.env config/database.yml}
set :linked_dirs, %w{bin log tmp/pids tmp/cache public/system}
set :rvm_ruby_version, '2.1.2'

namespace :deploy do
  desc 'Restart application'
  task :restart_unicorn do
    on roles :app, in: :sequence, wait: 5 do
      execute 'service unicorn upgrade'
    end
  end

  after :publishing, :restart_unicorn
end

namespace :setup do
  desc "Update '/etc/init.d/unicorn' script"
  task :unicorn do
    on roles :app do
      info "Updating '/etc/init.d/unicorn' script"
      sudo "cp #{release_path}/config/deploy/init.d/unicorn /etc/init.d/unicorn"
      sudo "chmod a+x /etc/init.d/unicorn"
    end
  end
end

after 'deploy:updated', 'setup:unicorn'

Gemfile

source 'https://rubygems.org'

# ...
gem 'capistrano', '~> 3.2.0'
gem 'capistrano-bundler', '~> 1.1.2'
gem 'capistrano-rails', '~> 1.1'
gem 'capistrano-rvm'
# ...