Update readme

README.md

@@ -13,3 +13,23 @@ serve HTML but this is planned for the (distant?) future.
 The two official client implementations are a stand alone TUI client for
 the unix terminal, and GNU Emacs. The API is simple and others are welcome
 to join the party at some point.
+
+## Docker
+**Database**
+
+Initialize with  
+```bash
+/bin/bash ./setup.sh --dbset
+```
+
+Mount to `/app/data.sqlite`
+
+**Environment variables**
+| Name          | Default | Description                           |
+|---------------|---------|---------------------------------------|
+| PORT          | 7099    | Port number to listen for connections |
+| HOST          | 0.0.0.0 | Host address to bind to               |
+| INSTANCE_NAME | BBJ     | BBJ's instance name                   |
+| ALLOW_ANON    | true    | Allow anonymous usage                 |
+| DEBUG         | false   | Enable debugging                      |
+| ADMIN         |         | Comma separated list of admin users   |