Use correct settings module for development

Dockerfile

@@ -66,6 +66,8 @@ RUN --mount=type=cache,uid=$USER_ID,gid=$GROUP_ID,target=/home/newsreader/.cache
 
 COPY --chown=newsreader:newsreader ./src /app/src
 
+ENV DJANGO_SETTINGS_MODULE=newsreader.conf.production
+
 # Note that the static volume will have to be recreated to be pre-populated
 # correctly with the latest static files. See
 # https://docs.docker.com/storage/volumes/#populate-a-volume-using-a-container
@@ -78,3 +80,5 @@ FROM backend AS development
 
 RUN --mount=type=cache,uid=$USER_ID,gid=$GROUP_ID,target=/home/newsreader/.cache/uv \
     uv sync --frozen --group development
+
+ENV DJANGO_SETTINGS_MODULE=newsreader.conf.docker

docker-compose.development.yml

@@ -6,6 +6,8 @@ services:
     build: &app-development-build
       target: development
     command: uv run --no-sync -- /app/src/manage.py runserver 0.0.0.0:8000
+    environment: &django-env
+      DJANGO_SETTINGS_MODULE: ${DJANGO_SETTINGS_MODULE:-newsreader.conf.docker}
     ports:
       - "${DJANGO_PORT:-8000}:8000"
     volumes:
@@ -17,6 +19,8 @@ services:
   celery:
     build:
       <<: *app-development-build
+    environment:
+      <<: *django-env
     volumes:
       - ./src/:/app/src