Include flexible mounts env variables and volume

docker-compose.yaml

@@ -35,9 +35,12 @@ services:
     container_name: backendcomposedtt
     image: hftstuttgart/dta-backend:latest
     user: "${UID}:${GID}"
+    environment:
+      - HOST_TEST_DIR=/tmp/dta-tests
+      - CONTAINER_TEST_DIR=/tmp/dta-tests
     volumes: 
       - /var/run/docker.sock:/var/run/docker.sock
-      - '/tmp/dta-tests:/tmp/dta-tests'
+      - '${HOST_TEST_DIR}:${CONTAINER_TEST_DIR}'
 volumes:
   mariadb_data_dtt:
     driver: local