Add build instructions

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

CONTRIBUTING.md

@@ -26,9 +26,14 @@ are very busy and read the mailing lists.
 ## Getting Started
 
 - Fork the repository on GitHub
-- Read the [README](README.md) for build and test instructions
 - Play with the project, submit bugs, submit pull requests!
 
+
+## Building
+
+Each plugin is compiled simply with `go build`.  A script, `build.sh`,
+is supplied which will build all the plugins in the repo.
+
 ## Contribution workflow
 
 This is a rough outline of how to prepare a contribution:

README.md

@@ -4,6 +4,8 @@
 # plugins
 Some CNI network plugins, maintained by the containernetworking team. For more information, see the individual READMEs.
 
+Read [CONTRIBUTING](CONTRIBUTING.md) for build and test instructions.
+
 ## Plugins supplied:
 ### Main: interface-creating
 * `bridge`: Creates a bridge, adds the host and the container to it.