docs: update readme

Author: pemrouz

README.md

@@ -2,6 +2,4 @@
 [![Coverage Status](https://coveralls.io/repos/rijs/sync/badge.svg?branch=master&service=github)](https://coveralls.io/github/rijs/sync?branch=master)
 [![Build Status](https://travis-ci.org/rijs/sync.svg)](https://travis-ci.org/rijs/sync)
 
-Synchronises resources between server and client whenever they change.
-
-The server can specify transformation functions to define the flow of data between server-client. See the [Primer](https://github.com/rijs/docs/blob/master/primer.md#5-sync) for more info.
+Synchronises resources between server and client whenever they change. When a resource changes, the update is streamed to the server or other connected clients. You can specify transformation functions on incoming and outgoing updates to control the flow of data on a per resource, per resource type, or global level. See the [Primer#Sync](https://github.com/rijs/docs/blob/master/primer.md#5-sync) for more info.