add healthcheck to Dockerfile

Dockerfile

@@ -293,9 +293,8 @@ WORKDIR "$DATA_DIR"
 VOLUME "$DATA_DIR"
 EXPOSE 8000
 
-# Optional:
-# HEALTHCHECK --interval=30s --timeout=20s --retries=15 \
-#     CMD curl --silent 'http://localhost:8000/admin/login/' || exit 1
+HEALTHCHECK --interval=30s --timeout=20s --retries=15 \
+    CMD curl --silent 'http://localhost:8000/health/' | grep -q 'OK'
 
 ENTRYPOINT ["dumb-init", "--", "/app/bin/docker_entrypoint.sh"]
 CMD ["archivebox", "server", "--quick-init", "0.0.0.0:8000"]