Deploy Rails 4 to AWS EC2(Ubuntu 14.04.4 LTS). Nginx, Puma, Capistrano3, PostgreSQL, RVM.

Capistrano Commands

Capistrano::Rails::Db
cap production deploy:db:abort_if_pending_migrations  # Run rake db:abort_if_pending_migrations
cap production deploy:db:create                       # Run rake db:create
cap production deploy:db:drop                         # Run rake db:drop
cap production deploy:db:migrate                      # Run rake db:migrate         Migrate the database (options: VERSION=x, VERBOSE=false, SCOPE=blog)
cap production deploy:db:migrate:down                 # Run rake db:migrate:down    Run the "down" for a given migration VERSION
cap production deploy:db:migrate:redo                 # Run rake db:migrate:redo    Rollback the database one migration and re migrate up (options: STEP=x, VERSION=x)
cap production deploy:db:migrate:reset                # Run rake db:migrate:reset   Reset your database using your migrations
cap production deploy:db:migrate:status               # Run rake db:migrate:status  Display status of migrations
cap production deploy:db:migrate:up                   # Run rake db:migrate:up      Run the "up" for a given migration VERSION
cap production deploy:db:reset                        # Run rake db:reset           Drop and recreate the database from db/schema.rb and load the seeds
cap production deploy:db:rollback                     # Run rake db:rollback        Roll the schema back to the previous version (specify steps w/ STEP=n)
cap production deploy:db:seed                         # Run rake db:seed            Load the seed data from db/seed.rb
cap production deploy:db:setup                        # Run rake db:setup           Create the database, load the schema, and initialize with the seed data
cap production deploy:db:version                      # Run rake db:version         Retrieve the current schema version number


Capistrano::Nginx
nginx:setup                                           # creates /etc/nginx/sites-available/APPLICATION.conf and links it to /etc/nginx/sites-enabled/APPLICATION.conf
nginx:stop                                            # invokes service nginx stop on server
nginx:start                                           # invokes service nginx start on server
nginx:restart                                         # invokes service nginx restart on server
nginx:reload                                          # invokes service nginx reload on server
nginx:force-reload                                    # invokes service nginx force-reload on server
nginx:enable_site                                     # creates symlink in sites-enabled directory
nginx:disable_site                                    # removes symlink from sites-enabled directory


Capistrano::Rails::Console
cap production rails:console                  # This will add a task rails:console
cap production rails:console sandbox=1        # You can also start a sandbox session


For more commands run:
cap -T

Server Setup

root# apt-get update
root# apt-get upgrade

root# adduser deployer
root# gpasswd -a deployer sudo

root# nano /etc/ssh/sshd_config
root# PermitRootLogin no
root# PasswordAuthentication yes
root# service ssh restart

root# exit

ssh deployer@server

Note:
ssh-keygen
cat ssh
nano ssh-authorized-key

deployer$ sudo apt-get -y install git-core curl zlib1g-dev build-essential libssl-dev libreadline-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt1-dev libcurl4-openssl-dev python-software-properties libffi-dev

deployer$ gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
deployer$ \curl -sSL https://get.rvm.io | bash -s stable
deployer$ source /home/deployer/.rvm/scripts/rvm
deployer$ rvm install 2.3.0 && rvm use --default 2.3.0
deployer$ echo "gem: --no-document" > ~/.gemrc
deployer$ gem install bundler
deployer$ gem install rails -v 5.0.0.beta3

deployer$ curl -sL https://deb.nodesource.com/setup_4.x | sudo -E bash -
deployer$ sudo apt-get install -y nodejs

deployer$ sudo apt-get install software-properties-common python-software-properties
deployer$ sudo add-apt-repository ppa:nginx/stable
deployer$ sudo apt-get update
deployer$ sudo apt-get -y install nginx
deployer$ sudo rm /etc/nginx/sites-available/default

deployer$ export LANGUAGE=en_US.UTF-8
deployer$ export LANG=en_US.UTF-8
deployer$ export LC_ALL=en_US.UTF-8
deployer$ locale-gen en_US.UTF-8
deployer$ sudo dpkg-reconfigure locales

deployer$ sudo apt-get -y install postgresql postgresql-contrib libpq-dev
deployer$ sudo pg_createcluster 9.3 main --start
deployer$ sudo -u postgres createuser deployer -s
deployer$ sudo -u postgres psql
postgres=# \password deployer
postgres=# \q

postgres=# sudo -u postgres createdb -O urlshortner urlshortner_production

deployer$ wget https://raw.githubusercontent.com/puma/puma/master/tools/jungle/upstart/puma-manager.conf
deployer$ wget https://raw.githubusercontent.com/puma/puma/master/tools/jungle/upstart/puma.conf
deployer$ nano puma.conf
SET:
setuid deployer
setgid deployer
SAVE:
ctrl + x
y
enter
deployer$ sudo cp puma.conf puma-manager.conf /etc/init
deployer$ sudo touch /etc/puma.conf
deployer$ sudo sh -c 'echo "deployer ALL=(ALL) NOPASSWD:ALL" > /etc/sudoers.d/deployer'

Setup Capistrano

ADD TO Gemfile:
group :development do
  gem 'capistrano', '3.5.0'
  gem 'capistrano-rvm'
  gem 'capistrano-nginx'
  gem 'capistrano3-puma'
  gem 'capistrano-rails'
  gem 'capistrano-rails-db'
  gem 'capistrano-rails-console'
  gem 'capistrano-upload-config'
  gem 'sshkit-sudo'
end

RUN:
your_app$ bundle install
your_app$ cap install

EDIT config/deploy.rb AS ATTACHED deploy.rb AND CHANGE VARIABLES IN IT
----------------------------------------------------
#Copy deploy.rb file:

# config valid only for current version of Capistrano
lock '3.5.0'

set :repo_url, 'git@bitbucket.org:test/testest.git'
# ask :branch, `git rev-parse --abbrev-ref HEAD`.chomp
set :user, 'deployer'
set :application, 'test'
set :rails_env, 'production'
server '00.00.00.000', user: "#{fetch(:user)}", roles: %w{app db web}, primary: true
set :deploy_to,       "/home/#{fetch(:user)}/apps/#{fetch(:application)}"
set :pty, true

set :linked_files, fetch(:linked_files, []).push('config/database.yml', 'config/secrets.yml', 'config/puma.rb')
set :linked_dirs, fetch(:linked_dirs, []).push('log', 'tmp/pids', 'tmp/cache', 'tmp/sockets', 'vendor/bundle', 'public/system', 'public/uploads')

set :config_example_suffix, '.example'
set :config_files, %w{config/database.yml config/secrets.yml}
set :puma_conf, "#{shared_path}/config/puma.rb"

set :puma_rackup, -> { File.join(current_path, 'config.ru') }
set :puma_state, "#{shared_path}/tmp/pids/puma.state"
set :puma_pid, "#{shared_path}/tmp/pids/puma.pid"
set :puma_bind, "unix://#{shared_path}/tmp/sockets/puma.sock"    #accept array for multi-bind
set :puma_conf, "#{shared_path}/puma.rb"
set :puma_access_log, "#{shared_path}/log/puma_error.log"
set :puma_error_log, "#{shared_path}/log/puma_access.log"
set :puma_role, :app
set :puma_env, fetch(:rack_env, fetch(:rails_env, 'production'))
set :puma_threads, [0, 8]
set :puma_workers, 0
set :puma_worker_timeout, nil
set :puma_init_active_record, true
set :puma_preload_app, false

----------------------------------------------
EDIT Capfile AS ATTACHED Capfile
#Capfile
require 'capistrano/setup'
require 'capistrano/deploy'
require 'capistrano/nginx'
require 'capistrano/rvm'
require 'capistrano/puma'
require 'capistrano/puma/nginx'
require 'capistrano/rails/migrations'
require 'capistrano/rails/db'
require 'capistrano/rails/console'
require 'capistrano/upload-config'
require 'sshkit/sudo'

Dir.glob('lib/capistrano/tasks/*.rake').each { |r| import r }


-------------------------------------------

#Production.rb
server '00.00.00.000', user: 'deployer', roles: %w{web app db}

-------------------------------------------


RUN:
your_app$ cp config/database.yml config/database.yml.example
your_app$ cp config/secrets.yml config/secrets.yml.example
your_app$ cap production config:init
your_app$ echo '/config/database.production.yml' >> .gitignore
your_app$ echo '/config/secrets.production.yml' >> .gitignore

EDIT WITH YOUR PARAMETERS:
/config/database.production.yml
/config/secrets.production.yml

RUN:
your_app$ rails g capistrano:nginx_puma:config

EDIT OR LEAVE AS IS:
config/deploy/templates/nginx_conf.erb
config/deploy/templates/puma.rb.erb

GIT COMMIT AND PUSH CHANGES

RUN:
your_app$ cap production deploy

CONGRATULATION! ALL DONE!
CHECK YOUR RUNNIG SERVER!

WAIT! ONE MORE THING TO DO.
FOR UPSTART PUMA SERVER ADD LINE WITH FULL PATH OF YOUR APP IN /etc/puma.conf.
RUN:
deployer$ sudo nano /etc/puma.conf

PASTE:
/home/deployer/apps/<<YOUR APP>>/current

SAVE:
ctrl + x
y
enter

FINALLY! YOU CAN RESTART SERVER TO CHECK PUMA AUTOSTART!
RUN:
deployer$ sudo shutdown -r now

Love the way you managed puma.

Thanks reuableahcim !!