How to install Postgresql-9.6 and PostGIS-2.3 on Ubuntu 17.04 (Zesty Zapus) in six easy steps (updated 31-05-2017).
  Install Ubuntu 17.04 (Zesty Zapus)   1.  check your Ubuntu version:-    lsb_release -a     Install Postgresql    2.  On the server or your PC (Terminal):-    sudo apt-get update   sudo apt-get install -y postgresql postgresql-contrib     Create a database and a user for access   Replace  DATABASE_NAME_HERE  and  USER_NAME_HERE  with the values you want to use.  # this will prompt you for a database password...also note the capital letter 'O' not number '0' (zero) below:-   3.  sudo -u postgres createuser -P USER_NAME_HERE   sudo -u postgres createdb -O USER_NAME_HERE DATABASE_NAME_HERE     Test Connection to Postgresql   4.  psql -h localhost -U USER_NAME_HERE DATABASE_NAME_HERE    Postgresql will ask you for your password. Then you should see the following:   DATABASE_NAME_HERE =>   To exit type:-   \q    To add PostGIS-2.3 support to the database   5.  sudo apt-get install -y postgis postgresql-9.6-postgis-2.3  # typing 'postgresql-9.5' instead of postgre...