Resources

Ubuntu Server - http://www.ubuntu.com/download/server
Digital Ocean - https://www.digitalocean.com/
Securing your Server - https://www.digitalocean.com/community/tutorials/an-introduction-to-securing-your-linux-vps
Setting up a firewall - https://www.digitalocean.com/community/tutorials/how-to-setup-a-firewall-with-ufw-on-an-ubuntu-and-debian-cloud-server 

Summary

updates and add usersudo apt-get update && sudo apt-get upgrade -y
adduser deploy
sudo usermod -aG sudo deploy
sudo apt-get install curl nano git libmysqlclient-dev coffeescript gawk g++ gcc make libreadline6-dev libssl-dev libyaml-dev libsqlite3-dev sqlite3 autoconf libgmp-dev libgdbm-dev libncurses5-dev automake libtool bison pkg-config libffi-dev -y

login as deploy user, install applicationgpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
\curl -sSL https://get.rvm.io | bash -s stable
source /home/deploy/.rvm/scripts/rvm
rvm install 2.3.1
echo 'gem: --no-document' >> ~/.gemrc
gem update --system
gem install bundler
git config --global user.email 'YOUR_EMAIL'
git config --global user.name 'YOUR_NAME'
ssh-keygen -t rsa -C "YOUR_EMAIL"
cat ~/.ssh/id_rsa.pub
git clone [email protected]:driftingruby/sample_application.git
cd sample_application
bundle
echo 'export RAILS_ENV=production' >> ~/.bashrc
source ~/.bashrc
gem install passenger

install passenger dependenciessudo apt-get install apache2 libcurl4-openssl-dev apache2-dev libapr1-dev libaprutil1-dev

install mysql serversudo apt-get install mysql-server

configure application settingsnano config/database.yml
nano config/secrets.yml

install passenger apache modulesudo a2enmod headers
passenger-install-apache2-module

/etc/apache2/apache2.conf   LoadModule passenger_module /home/deploy/.rvm/gems/ruby-2.3.1/gems/passenger-5.0.28/buildout/apache2/mod_passenger.so
   <IfModule mod_passenger.c>
     PassengerRoot /home/deploy/.rvm/gems/ruby-2.3.1/gems/passenger-5.0.28
     PassengerDefaultRuby /home/deploy/.rvm/gems/ruby-2.3.1/wrappers/ruby
   </IfModule>

/etc/apache2/sites-enabled/000-default.confPassengerMaxPoolSize 4
  <VirtualHost *:80>
      Header add Strict-Transport-Security max-age=31536000
      DocumentRoot /home/deploy/sample_application/public
      <Directory /home/deploy/sample_application/public>
         Header unset ETag
         AllowOverride all
         Options -MultiViews
         Order allow,deny
         Allow from all
         Require all granted
      </Directory>
      PassengerMinInstances 2
  </VirtualHost>

If you need to create and configure self-signed certificatessudo mkdir /etc/apache2/ssl
cd /etc/apache2/ssl
sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout apache.key -out apache.crt
sudo a2enmod ssl

enable apache module rewritesudo a2enmod rewrite

/etc/apache2/sites-enabled/000-default.conf# Redirects 80 traffic to 443 
<VirtualHost *:80>
    Redirect permanent "/" "https://107.170.118.82/"
</VirtualHost>

<VirtualHost *:443>
    Header add Strict-Transport-Security max-age=31536000
    DocumentRoot /home/deploy/sample_application/public
    <Directory /home/deploy/sample_application/public>
       Header unset ETag
       AllowOverride all
       Options -MultiViews
       Order allow,deny
       Allow from all
       Require all granted
    </Directory>
    SSLEngine on
    SSLCertificateFile /etc/apache2/ssl/apache.crt
    SSLCertificateKeyFile /etc/apache2/ssl/apache.key
    PassengerMinInstances 2
</VirtualHost>

restart apachesudo service apache2 restart

locking down sshsudo nano /etc/ssh/sshd_config
sudo su
sudo mv /root/.ssh/authorized_keys ~/.ssh/
sudo chown -R deploy ~/.ssh/authorized_keys
sudo service ssh restart

installing and configuring ufwsudo apt-get install ufw
sudo ufw status
sudo ufw allow 22222/tcp
sudo ufw allow www/tcp
sudo uff allow 443/tcp
sudo ufw enable