fix: add volume mapping for client service

the client container needs DJANGO_STORAGE_DIR to be
`/home/calitp/app/data` because the nginx.conf location blocks use that
base path to serve media files.

the volume mapping is needed so that the container has access to the
django.db file and the uploads/ directory from the host side of the
mapping.

compose.yml

@@ -9,6 +9,8 @@ services:
     env_file: .env
     ports:
       - "${DJANGO_LOCAL_PORT:-8000}:8000"
+    volumes:
+      - ./:/home/calitp/app/data # matches the path in nginx.conf for static / media files. set your DJANGO_STORAGE_DIR to `/home/calitp/app/data` so the container can access `django.db` and `uploads/`.
 
   dev:
     build: