Remove variable defaults

These are not set whenever a merged compose file is used

docker-compose.development.yml

@@ -5,6 +5,8 @@ volumes:
   node-modules:
 
 services:
+  db:
+    env_file: ./.development.env
   celery:
     env_file: ./.development.env
     environment:
@@ -15,12 +17,12 @@ services:
   django:
     build:
       target: development
-    command: python /app/src/manage.py runserver 0.0.0.0:${DJANGO_PORT:-8000}
+    command: python /app/src/manage.py runserver 0.0.0.0:8000
     env_file: ./.development.env
     environment:
       - DJANGO_SETTINGS_MODULE=newsreader.conf.docker
     ports:
-      - "${DJANGO_PORT:-8000}:${DJANGO_PORT:-8000}"
+      - "${DJANGO_PORT:-8000}:8000"
     volumes:
       - ./src:/app/src
       - static-files:/app/src/newsreader/static