Mention new-build in README

Author: hvr

README.md

@@ -59,6 +59,14 @@ Clone the repository:
 
 and then proceed using your favourite build tool.
 
+###### Using [`cabal new-build`](http://cabal.readthedocs.io/en/latest/nix-local-build-overview.html)
+
+```bash
+cabal new-build -w ghc-8.2.1
+# build & run the test suite
+cabal new-test -w ghc-8.2.1
+```
+
 ###### Using Cabal sandboxes
 
 ```bash