readme for apidoc

extensions/yii/apidoc/README.md

@@ -25,7 +25,17 @@ to the require section of your composer.json.
 Usage
 -----
 
-TDB
+To generate API documentation, run the `apidoc` command.
+
+```
+vendor/bin/apidoc source/directory ./output
+```
+
+By default the `offline` template will be used. You can choose a different templates with the `--template=name` parameter.
+Currently there is only the `offline` template available.
+
+You may also add the `yii\apidoc\commands\RenderController` to your console application class map and
+run it inside of your applications console app.
 
 Creating your own templates
 ---------------------------