Remove unnecessary create_extension

postgres-hstore/Dockerfile

@@ -1,3 +0,0 @@
-FROM postgres:9.6.17@sha256:5b39dd4a26a02fee26902c84d8bafb2eb0ab9a2874fb0be22056107aa6508899
-MAINTAINER Piotr Dobrowolski
-ADD create_extension.sh /docker-entrypoint-initdb.d/create_extension.sh

postgres-hstore/create_extension.sh

@@ -1,16 +0,0 @@
-#!/bin/bash
-set -e
-
-# Because both template1 and the user postgres database have already been created,
-# we need to create the hstore extension in template1 and then recreate the postgres database.
-#
-# Running CREATE EXTENSION in both template1 and postgres can lead to
-# the extensions having different eid's.
-psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --dbname template1 <<EOSQL
-    CREATE EXTENSION hstore;
-    CREATE EXTENSION ltree;
-    CREATE EXTENSION pg_trgm;
-    DROP DATABASE $POSTGRES_USER;
-    CREATE DATABASE $POSTGRES_USER TEMPLATE template1;
-EOSQL
-