README.md in rest-builder-0.9.0 vs README.md in rest-builder-0.9.1

@@ -21,10 +21,10 @@
 
 ## FEATURES:
 
 * Modular interface for REST clients similar to WSGI/Rack for servers.
 * Concurrent requests with synchronous or asynchronous interfaces with
-  threads.
+  threads via [promise_pool][].
 
 ## WHY?
 
 This was extracted from [rest-core][] because rest-core itself is getting
 too complex, and this would be the new core of rest-core. Naming it