communication: sync protocol adapater to add psync

refs: #4082

Change-Id: Ibe4649e709dfbc3cdc1f2afbfc4ff03f75a3f136
diff --git a/docs/INSTALL.rst b/docs/INSTALL.rst
index d567598..da66e87 100644
--- a/docs/INSTALL.rst
+++ b/docs/INSTALL.rst
@@ -21,6 +21,15 @@
 
        https://github.com/named-data/ChronoSync#build
 
+-  PSync library:
+
+Download the PSync library and build it according to the instructions at the following
+address:
+
+   ::
+
+       https://github.com/named-data/PSync#build
+
 Build
 -----