README.md: refer to a couple of interesting badges

Author: peti

hackage-db/README.md

@@ -0,0 +1,7 @@
+hackage-db
+==========
+
+[![hackage release](https://img.shields.io/hackage/v/hackage-db.svg?label=hackage)](http://hackage.haskell.org/package/hackage-db)
+[![stackage LTS package](http://stackage.org/package/hackage-db/badge/lts)](http://stackage.org/lts/package/hackage-db)
+[![stackage Nightly package](http://stackage.org/package/hackage-db/badge/nightly)](http://stackage.org/nightly/package/hackage-db)
+[![travis build status](https://img.shields.io/travis/peti/hackage-db/master.svg?label=travis+build)](https://travis-ci.org/peti/hackage-db)