install.sh

#!/bin/bash

# remove existing 9.1 installation
sudo /etc/init.d/postgresql stop
sudo apt-get --force-yes -fuy remove --purge postgresql postgresql-9.1 postgresql-client

# install zip
sudo apt-get install -y zip

# install 9.3
sudo apt-get install python-software-properties
sudo add-apt-repository 'deb http://apt.postgresql.org/pub/repos/apt/ precise-pgdg main'
sudo apt-get update
sudo apt-get install -y postgresql-9.3 postgresql-contrib

# update the postgres config files
sudo /bin/bash -c "cat <<EOF > /etc/postgresql/9.3/main/pg_hba.conf
local   all             postgres                                trust
local   all             all                                     trust
host    all             all             127.0.0.1/32            trust
host    all             all             ::1/128                 trust
EOF"

# restart
sudo /etc/init.d/postgresql restart

Modified Brads install script by adding 'postgresql-contrib'.
Needed for PSQL to use EXTENSIONs