add transfer directory in database container

docker/templates/db_data_readme.md

+# TARGET: docker/containers/db-server/var_tmp_db-data/readme.txt
+
+# Info
+
+content of `docker/containers/db_server/var_tmp_db-data/` will be visible in the database container as `/var/tmp/db-data/`. It is a helper to transfer/ import sqldumps.

docker/templates/docker-compose.yml

@@ -62,8 +62,9 @@ services:
       MYSQL_PASSWORD: '${MYSQL_PASS}'
       MYSQL_DATABASE: '${MYSQL_DB}'
     volumes:
-      # - ./containers/db-server/db_data:/var/lib/mysql
       - ./containers/db-server/mariadb/my.cnf:/etc/mysql/conf.d/my.cnf
+      - ./containers/db-server/mariadb/dot_my.cnf:/root/.my.cnf
+      - ./containers/db-server/var_tmp_db-data/:/var/tmp/db-data
     healthcheck:
       test: mysqladmin ping -h 127.0.0.1 -u root --password=$$MYSQL_ROOT_PASSWORD
       interval: 5s