volume in oracle database not saving user information

I create a local oracle database but my volume is not saving my user. I do the following.

1) docker login
2) docker-compose up
3) docker exec -it <container id> bin/bash
4) sqlplus / as sysdba
5) alter session set "_ORACLE_SCRIPT"=true;
6) create user admin identified by admin;
7) GRANT CREATE SESSION, CREATE DATABASE LINK, CREATE MATERIALIZED VIEW, 
   CREATE PROCEDURE, CREATE PUBLIC SYNONYM, CREATE ROLE,CREATE SEQUENCE, 
   CREATE SYNONYM, CREATE TABLE,
   CREATE TRIGGER, CREATE TYPE, CREATE VIEW, UNLIMITED TABLESPACE to admin;

docker-compose.yml

version: "3"
services:
  database:
    image: "store/oracle/database-enterprise:12.2.0.1-slim"
    ports:
      - "1521:1521"
    environment:
      - DB_SID=XE
      - DB_PASSWD=admin
    volumes:
      - oracle-database:/opt/oracle/oradata
 volumes:
   oracle-database:

However when I run docker-compose down and then up I have to respeat all the step again confirming the volume is not working. Has someone ran into this issue before?

Source: StackOverflow