add relative-urls setting

README.md

@@ -35,7 +35,7 @@ Generate the content and run the server:
 
 ```bash
 $ pelican content
-$ pelican --listen
+$ pelican --listen --relative-urls
 ```
 
 Then the site is available at the following URL:
@@ -59,7 +59,7 @@ And then the Pelican development server will automatically reload
 when you make changes. It is also possible to use:
 
 ```bash
-$ pelican --autoreload --listen
+$ pelican --autoreload --listen --relative-urls
 ```
 
 However, this will not automatically refresh your browser page.