Merge branch 'f-compose' into f-file-references

.docker/docker-compose.yml

+version: '3.6'
+services:
+  sqldb:
+    image: mariadb:10.5
+    volumes:
+      - type: volume
+        source: "caosdb-sqldata"
+        target: /var/lib/mysql
+    environment:
+      MYSQL_ROOT_PASSWORD: caosdb1234
+    networks:
+      # available on port 3306, host name 'sqldb'
+      - caosnet
+    ports:
+      - 3306:3306
+
+
+# A well-defined network for caosdb
+volumes:
+    caosdb-sqldata:
+networks:
+  caosnet:
+    driver: bridge