mount styles/ into notebooks container for nature.py import

The acodb_explorer notebook imports from styles/nature.py via sys.path.
Without the volume mount, the container couldn't find the module.

refs #53

compose.yml

@@ -191,6 +191,7 @@ services:
       - ./data:/home/kert/data
       - ./zotero/data:/home/kert/zotero:ro
       - ./src:/home/kert/src:ro
+      - ./styles:/home/kert/styles:ro
       - ./stack.toml:/home/kert/stack.toml:ro
     deploy:
       resources: