Added usage doc

Author: forman

dashipy/README.md

@@ -1,11 +1,53 @@
 # dashi 
 
-Dashi is a demo for server-configured panels using Plotly + Tornado. 
+Dashi is a framework for server-configured panels. 
 
-### Run server
+## Run demo server
 
 ``` bash
 mamba env create
 conda activate dashi
 python -m dashipy.server 
 ```
+
+## How to use the framework
+
+### 1. Implement the possible contributions
+
+Implement the application-specific contributions that users 
+can add to their extensions.
+
+As an example, see [`panel.py` of the demo](dashipy/demo/contribs/panel.py).
+
+### 2. Define the contributions points
+
+Define the possible contribution points in your application.
+
+As an example, see [`server.py` of the demo](dashipy/demo/server.py):
+
+```python
+from dashipy import Extension
+from dashipy.demo.contribs import Panel
+
+Extension.add_contrib_point("panels", Panel)
+```
+
+### 3. Load the extensions
+
+Load the extensions that augment your application.
+
+As an example, see [`server.py` of the demo](dashipy/demo/server.py):
+
+```python
+from dashipy import ExtensionContext
+
+ext_ctx = ExtensionContext.load(app_ctx, extension_refs)
+```
+
+### 4. Publish the extensions 
+
+Implement the Dashi API in your application-specific webserver using
+the controller implementations in `dashipy.controllers`. 
+
+As an example, see [`server.py` of the demo](dashipy/demo/server.py).
+