use custom docker config in dockerized tests

tests/docker-compose.yml

@@ -4,7 +4,8 @@ services:
   php:
     build: ..
     working_dir: /project
-    #volumes:
+    volumes:
+      - ../tests/data/config-docker.php:/project/tests/data/config.php
       # Enable for debugging, enabling tests might be slow for file access (data) on host-volume
       #- ../tests:/project/tests
       # - ../framework:/project/framework