Deploying a Rails App on Ubuntu 14.04 with Capistrano, Nginx, and Puma

setting_deploy.sh

# Step 1 — Installing Nginx
$ sudo apt-get update
$ sudo apt-get upgrade -y
$ sudo apt-get install curl git-core nginx -y

# Step 2 — Installing Databases
# before install , update apt-get
$ sudo apt-get update

# choose one or both,
# In MYSQL: 
$ sudo apt-get install mysql-server mysql-client libmysqlclient-dev

# In PostgreSQL
$ sudo apt-get install postgresql postgresql-contrib libpq-dev

# Step 3 — Installing RVM and Ruby
# Before installing RVM, you need to import the RVM GPG Key:
$ gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3

# Then install RVM to manage our Rubies:
$ curl -sSL https://get.rvm.io | bash -s stable

# after that :
#  We then need to run the requirements command to automatically install required dependencies and files for RVM and Ruby to function properly:
$ source ~/.rvm/scripts/rvm
$ rvm requirements

# Step 4 — Installing Ruby 
$ rvm install 2.2.1
$ rvm use 2.2.1 --default

# Step 5 — Installing Rails and Bundler
@ gem install rails -V --no-ri --no-rdoc
@ gem install bundler -V --no-ri --no-rdoc

# Step 6 — Setting up SSH Keys
# First shake hands with GitHub, Bitbucket, or any other Git Remote where the codebase for your Rails app is hosted:
$ ssh -T git@bitbucket.org
$ ssh -T git@github.com

# Don't worry if you get a Permission denied (publickey) message. Now, generate a SSH key (a Public/Private Key Pair) for your server:
$ ssh-keygen -t rsa 

# you should now be able to clone your git repository (over the SSH Protocol, not HTTP) without entering your password:
# exmp..
$ git clone git@example.com:username/appname.git

# Add your local SSH Key to your Droplet's Authorized Keys file (remember to replace the port number with your customized port number):
$ cat ~/.ssh/id_rsa.pub | ssh -p your_port_num deploy@your_server_ip 'cat >> ~/.ssh/authorized_keys'

# Step 7 — Adding Deployment Configurations in the Rails App
# create configuration files for Nginx and Capistrano in your Rails application. Start by adding these lines to the Gemfile in the Rails App:
group :development do
    gem 'capistrano',         require: false
    gem 'capistrano-rvm',     require: false
    gem 'capistrano-rails',   require: false
    gem 'capistrano-bundler', require: false
    gem 'capistrano3-puma',   require: false
end

gem 'puma'
# After bundling, run the following command to configure Capistrano:
$ cap install

# In Capfile
# Load DSL and Setup Up Stages
require 'capistrano/setup'
require 'capistrano/deploy'

require 'capistrano/rails'
require 'capistrano/bundler'
require 'capistrano/rvm'
require 'capistrano/puma'

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