updated README

jupyter/README.md

@@ -13,6 +13,22 @@ The images these files produce contain everything you could possibly want in a j
 
 To build this image, run `build/build.fish.` Edit the script to customize the image.
 
+## Configuration
+
+Change the permissions on the configuration volume (see `docker-compose.yml`) if you get errors.
+
+You may want to add the following lines to `jupyter_notebook_config.py`:
+
+```
+c.ServerApp.local_hostnames = ["localhost", "0.0.0.0"]
+c.ServerApp.token = "a_long_random_string"
+```
+
+The first sets `0.0.0.0` to the allowed local hostname list. This prevents a possible "connection reset" when connecting to the docker container. Opens jupyter up to the outside internet, but you should have your inbound ports firewalled off anyway.
+
+The second line sets a persistent token. If this config value is unset, jupyter will generate a new one on each run, making it hard to make a one-click bookmark.
+
+
 
 ## Image contents
  - jupyterlab, jupyterhub, notebook