Update README.md

README.md

 The Transmission RSS plugin can optionally be run as a separate container. It allow to download torrents based on an RSS URL, see [Plugin page](https://github.com/nning/transmission-rss).
 
 ```
-$ docker run -d -e "RSS_URL=http://.../xxxxx.rss" \
-      --link <transmission-container>:transmission \--link
+$ docker run -d \
+      -e "RSS_URL=<URL>" \
+      --link <transmission-container>:transmission \
+      --name "transmission-rss" \
+      haugene/transmission-rss
 ```
 
 #### Use docker env file