How To Install PostgreSQL 9.6 On Debian 9.1 stretch

PostgreSQL (simply known as Postgres) is an object-relational database management system (ORDBMS), available for many platforms including Linux, Microsoft Windows, FreeBSD, HP-UX, AIX, Solaris, and Mac OS. PostgreSQL is released under the PostgreSQL License, a free and open source permissive software license, developed by the PGDG (PostgreSQL Global Development Group), a group of individual volunteers and corporate companies.