diff --git a/demo/Dockerfile b/demo/Dockerfile
new file mode 100644
index 0000000..01cb5b6
--- /dev/null
+++ b/demo/Dockerfile
@@ -0,0 +1,23 @@
+FROM ubuntu:22.04
+ENV DEBIAN_FRONTEND=noninteractive
+ENV NODE_VERSION=16.17.1
+
+RUN apt-get update \
+ && apt-get -y dist-upgrade \
+ && apt-get -y install git sudo curl
+
+# cache some of the bigger installs
+RUN apt-get -y install python3-pip npm
+RUN python3 -m pip install --upgrade pip jupyterhub
+
+# Install nodejs v16 (not available yet on apt).
+ENV NVM_DIR=/root/.nvm
+RUN curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.1/install.sh | bash
+RUN . "$NVM_DIR/nvm.sh" && nvm install ${NODE_VERSION}
+RUN . "$NVM_DIR/nvm.sh" && nvm use v${NODE_VERSION}
+RUN . "$NVM_DIR/nvm.sh" && nvm alias default v${NODE_VERSION}
+ENV PATH="/root/.nvm/versions/node/v${NODE_VERSION}/bin/:${PATH}"
+
+RUN git clone https://github.com/jupyter/nbgrader /srv/nbgrader/nbgrader
+WORKDIR /srv/nbgrader/nbgrader/demos
+CMD ./restart_demo.sh demo_multiple_classes
diff --git a/demo/README.md b/demo/README.md
new file mode 100644
index 0000000..66b0a7a
--- /dev/null
+++ b/demo/README.md
@@ -0,0 +1,64 @@
+# Testing out nbgrader quickstart
+
+```shell
+python3 -m venv venv
+pip install -r requirements.txt
+mkdir exchange
+```
+
+```shell
+nbgrader quickstart hydro-mod-1
+cd hydro-mod-1
+```
+
+To `nbgrader_config.py` add `c.Exchange.root = "<cwd>/../exchange"
+`
+
+```
+jupyter lab
+```
+
+## Create student version
+
+```shell
+mkdir -p submitted/student1
+cp -r release/* submitted/student1/
+```
+
+## JupyterHub
+
+Follow https://nbgrader.readthedocs.io/en/stable/configuration/jupyterhub_config.html#example-use-case-multiple-classes
+and
+https://github.com/jupyter/nbgrader/tree/main/demos/demo_multiple_classes
+
+```
+docker build -t nbgraderhub .
+docker run -p 8000:8000 nbgraderhub
+```
+
+Goto http://localhost:8000
+
+Login with
+* instructor1: instructor1
+* student1: student1
+
+To edit assignemt
+1. As instructor1
+1. Goto Nbgrader -> Courses -> select course101
+1. Authorize yourself
+1. You can now edit the ps1 assigment in Formgrader
+
+To fetch assigment
+
+1. As student1
+1. Goto Nbgrader -> Assignment list
+1. Fetch ps1
+
+# TODO
+
+* [x] JupyterHub
+* [x] Multiple users
+* [x] Multiple courses
+* R
+* oauth or user sync
+* 
diff --git a/demo/requirements.txt b/demo/requirements.txt
new file mode 100644
index 0000000..ca0093e
--- /dev/null
+++ b/demo/requirements.txt
@@ -0,0 +1,2 @@
+jupyterlab
+nbgrader
diff --git a/technology_stack.md b/technology_stack.md
index b3df464..a3e81eb 100644
--- a/technology_stack.md
+++ b/technology_stack.md
@@ -27,10 +27,18 @@ Autograding: Secure grading of student code.
 
 https://okpy.org/
 
+# cocalc
+
+CoCalc is a virtual online workspace for calculations, research, collaboration and authoring documents. Your web browser is all you need to escape the confined space of your desktop and move to the cloud. This guide explains the features of CoCalc in depth and shows how you can use them productively.
+
+https://cocalc.com/
+https://github.com/sagemathinc/cocalc
+
 # e2x
 
 * https://github.com/DigiKlausur/e2xhub - A JupyterHub extension for simplifying course management for teaching and exams
 * https://github.com/DigiKlausur/e2xgrader - e2xgrader is an add-on for nbgrader that adds functionality for teachers and students. e2xgrader introduces new cell types and tools for graders (per question grading view, authoring component, pen-based grading) and students (assignment toolbar, exam toolbar, restricted notebook extension).
+  * notebook extension, not a lab extension
 
 
 # Brightspace
@@ -74,3 +82,13 @@ https://github.com/LibreTexts/ngshare - nbgrader sharing service
 * https://github.com/jupyterhub/hubshare - A directory sharing service for JupyterHub
 * https://github.com/jupyterhub/zero-to-jupyterhub-k8s/issues/174 - nbgrader support in JupyterHub on Kubernetes
 
+# GitHub Classroom
+
+https://docs.github.com/en/education/manage-coursework-with-github-classroom/get-started-with-github-classroom
+
+- can link with LMS google classroom, canvas, moodle, sakai
+
+# abc-classroom
+
+The abc-classroom package is designed for course instructors who are using GitHub Classroom to distribute and collect assignments to and from students.
+https://abc-classroom.readthedocs.io/