try to implement the global containerization

docker/backup/Dockerfile

@@ -0,0 +1,14 @@
+FROM alpine:latest
+
+RUN apk add --no-cache mariadb-client bash dcron
+
+RUN mkdir -p /backups
+RUN mkdir -p /etc/periodic/daily
+
+COPY backup_db.sh /etc/periodic/daily/backup_db
+COPY entrypoint.sh /entrypoint.sh
+
+RUN chmod +x /etc/periodic/daily/backup_db
+RUN chmod +x /entrypoint.sh
+
+ENTRYPOINT ["/entrypoint.sh"]