Fix HuggingFace and NLTK cache PermissionError in Docker

The entrypoint uses `su -p app` which preserves HOME=/root from the
root user. HuggingFace and NLTK default to ~/cache paths, resolving
to /root/ which the app user cannot write to.

Set HF_HOME and NLTK_DATA env vars to writable directories owned by
the app user.

Author: patrick91

backend/Dockerfile

@@ -73,9 +73,10 @@ ENV LIBRARY_PATH=/lib:/usr/lib LD_LIBRARY_PATH=/lib:/usr/lib
 RUN apt-get update -y && apt-get install -y curl
 
 RUN groupadd -r app && useradd -r -g app app && mkdir -p ${FUNCTION_DIR} && chown -R app:app ${FUNCTION_DIR} \
-    && mkdir -p /home/app/.cache/huggingface && chown -R app:app /home/app/.cache
+    && mkdir -p /home/app/.cache/huggingface /home/app/nltk_data && chown -R app:app /home/app/.cache /home/app/nltk_data
 
 ENV HF_HOME=/home/app/.cache/huggingface
+ENV NLTK_DATA=/home/app/nltk_data
 
 COPY --chown=app:app --from=js-stage ${FUNCTION_DIR}/dist/*.html ${FUNCTION_DIR}/custom_admin/templates/astro/
 COPY --chown=app:app --from=js-stage ${FUNCTION_DIR}/dist/widgets/*.html ${FUNCTION_DIR}/custom_admin/templates/astro/widgets/