Initiate multiple database Postgresql Docker

create_db_and_users.sh

#!/bin/sh

if [ -n "$POSTGRES_DBS" ]; then
	IFS=\|
	for s in $POSTGRES_DBS ; do
		pass=$(echo "$s" | sed 's/.*->//');
		user=$(echo "$s" | sed 's/->.*//');
		db=$user"_db";
		
		psql --username "$POSTGRES_USER" <<-EOSQL
	    	CREATE USER $user WITH PASSWORD '$pass';
	    	CREATE DATABASE $db;
	    	REVOKE CONNECT ON DATABASE $db FROM PUBLIC;
	    	GRANT ALL PRIVILEGES ON DATABASE $db TO $user;
	    	ALTER DATABASE $db OWNER TO $user;
		EOSQL
	done
fi

docker-compose.yml

  postgres:
    image: postgres:12.1-alpine
    restart: always
    volumes:
      - ./postgres_init:/docker-entrypoint-initdb.d
    environment:
      - POSTGRES_USER=P0stgr3sSup3rUs3r
      - POSTGRES_PASSWORD=SomeAdminPassword
      - POSTGRES_DBS=some_user->some_password|some_other_user->some_other_password