rails vps deployment without ripping your eyes out

deploy_prep.sh

# create a deploy user, and add them to sudoers
adduser deploy
gpasswd -a deploy sudo

# generate a key so you can just pop it on your github and pull your repo down from there
ssh-keygen -t rsa -C "your_email@example.com"
# test the connection so it adds the key to your authorized hosts list
ssh -T git@github.com

# add the phussion passenger package server key, and binaries source to to your apt packages list
apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 561F9B9CAC40B2F7
echo 'deb https://oss-binaries.phusionpassenger.com/apt/passenger trusty main' > /etc/apt/sources.list.d/passenger.list
chown root: /etc/apt/sources.list.d/passenger.list
chmod 600 /etc/apt/sources.list.d/passenger.list

# update your packages list so you've got all the latest dependency lists
sudo apt-get update
# install all of the stuff neccessary to build ruby, rails, and install postgres, apache2, and passenger
sudo apt-get install build-essential libssl-dev libyaml-dev libreadline-dev openssl curl git-core zlib1g-dev bison libxml2-dev libxslt1-dev libcurl4-openssl-dev libsqlite3-dev postgresql-9.3 libpq-dev apache2 libapache2-mod-passenger -y

# can probably get this script down to like 5 minutes if you use a ppa for the latest ruby
wget http://cache.ruby-lang.org/pub/ruby/2.2/ruby-2.2.2.tar.gz
tar -xzf ruby-2.2.2.tar.gz
cd ruby-2.2.2
./configure
make
make install

# enable apache2 passenger module
a2enmod passenger
service apache2 restart

# make damn sure that we're using our freshly added ruby and not the old system one
# (might not have to do this if you go the ppa route)
rm /usr/bin/ruby
ln -s /usr/local/bin/ruby /usr/bin/ruby

# git clone down your project into the deploy users home directory
# eg. /home/deploy/my_app

# apache2 config points to the public folder in your app
# eg. /home/deploy/my_app/public

project_dir="my_app"
cat > /etc/apache2/sites-available/deploy.conf <<EOF
<VirtualHost *:80>
    ServerName example.com
    ServerAlias www.example.com
    ServerAdmin webmaster@localhost
    DocumentRoot /home/deploy/$project_dir/public
    RailsEnv production
    ErrorLog \${APACHE_LOG_DIR}/error.log
    CustomLog \${APACHE_LOG_DIR}/access.log combined
    <Directory "/home/deploy/$project_dir/public">
        Options FollowSymLinks
        Require all granted
    </Directory>
</VirtualHost>
EOF

# disable the default apache2 page
a2dissite 000-default
# enable your new apache passenger site config
a2ensite deploy
service apache2 restart

If you have issues, you're gonna wanna check your logs/production.log and /var/logs/apache2/error.log to find out the situation you're in.

Also, there are some irritating rails secret setting of environmental variables to take care of.