updated docker install doc.

doc/install-docker.md

@@ -27,9 +27,19 @@ The container already documented to expose 80, 443 and 1935 ports, make sue to r
 
 ### Start Kaltura container
 ```bash
-docker run -d --name=kaltura -p 80:80 -p 443:443 -p 1935:1935 kaltura/server
+docker run -d --name=kaltura -p 80:80 -p 443:443 -p 1935:1935 -p 88:88 -p 8443:8443 kaltura/server
 ```
 
+Port 1935 TCP is the default RTMP port, required for live streaming
+Port 88 and 8443 are the default ports for Nginx, which loads the Nginx VOD module.
+You can control these ports with the following answer file vars:
+```
+VOD_PACKAGER_PORT
+RTMP_PORT
+```
+When installing interactively, you will be prompted for these values.
+
+
 ### Start of Kaltura Configuration
 
 ```bash