Add instructions for new Docker workflow options

README.md

@@ -12,10 +12,29 @@ $ git submodule update --init --recursive
 1. Install `make`.
 2. Install `docker`
 3. Build (export) site to `_site` directory:
+
 ```shell
 $ make build
 ```
+
 4. Serve site at `0.0.0.0:4000`:
+
 ```shell
 $ make serve
 ```
+
+### Generate Static Files
+
+1. Output static files in `_site` directory:
+
+```shell
+$ make _site
+```
+
+### Cleanup
+
+1. Remove all build artifacts:
+
+```shell
+$ make fullclean
+```