update build docs

Author: Jeff McCormick

docs/build.asciidoc

@@ -4,7 +4,10 @@ v1.0.0, {docdate}
 == Overview
 
 This document describes how to build from source code the
-Postgres Operator.
+Postgres Operator.  If you don't want to build the images
+from source, you can download them from the following:
+ * Dockerhub (crunchydata/lspvc and crunchydata/postgres-operator images)
+ * Github Releases  (pgo client and client configuration files, extracted to your $HOME)
 
 === Requirements