README: Add compatibility/coverage matrix

as suggested in sass/node-sass#655

README.md

@@ -3,6 +3,28 @@ node-sass-binaries
 
 This repository contains the native bindings that are published to NPM as part of [node-sass](https://github.com/sass/node-sass).
 
+## Compatibility
+
+The precompiled native bindings are available for [Node.js](http://nodejs.org/) and [io.js](https://iojs.org/) on the most common platforms.
+
+### Node.js 0.12
+
+- Windows (ia32 + x64)
+- OS X (x64)
+- Linux (ia32 + x64)
+
+### Node.js 0.10
+
+- Windows (ia32 + x64)
+- OS X (x64)
+- Linux (ia32 + x64)
+
+### io.js 1.2
+
+- Windows (ia32 + x64)
+- OS X (x64)
+- Linux (ia32 + x64)
+
 ## Copyright
 
 Copyright (c) 2013 Andrew Nesbitt. See [LICENSE](https://github.com/sass/node-sass-binaries/blob/master/LICENSE) for details.