Merge pull request FDio#4 from mestery/readme

Add some notes on prerequisites to build on a Mac

Author: fkautz

README.md

@@ -3,3 +3,11 @@
 A Network Service Mesh is an extension of the Service Mesh concept common in applications to Network Services.  It is part of an attempt to reimagine NFV in a Cloud-native way.
 
 - [Network Service Mesh Intro slides](https://docs.google.com/presentation/d/1C3r91ev0tWnFFUjiV4W84Hp965YGR1D9lChZo73Jwq0/edit#slide=id.g375263091c_1_0)
+
+## Prerequisites to build
+
+On a Mac:
+
+- brew install make
+- brew install golang protobuf
+- go get -u github.com/golang/protobuf/protoc-gen-go