README: Add CI, doc and coverage badges

README.md

@@ -1,5 +1,4 @@
-mapdecode
-=========
+# mapdecode [![GoDoc][doc-img]][doc] [![Build Status][ci-img]][ci] [![Coverage Status][cov-img]][cov]
 
 mapdecode implements a generic `interface{}` decoder. It allows implementing
 custom YAML/JSON decoding logic only once. Instead of implementing the same
@@ -23,13 +22,18 @@ This package relies heavily on [mapstructure] for much of its functionality.
 
   [mapstructure]: https://github.com/mitchellh/mapstructure
 
-Status
-------
+## Status
 
 Beta
 
 -------------------------------------------------------------------------------
 
 Released under the [MIT License].
 
-  [MIT License]: LICENSE.txt
+[MIT License]: LICENSE.txt
+[doc-img]: https://godoc.org/github.com/uber-go/mapdecode?status.svg
+[doc]: https://godoc.org/github.com/uber-go/mapdecode
+[ci-img]: https://travis-ci.org/uber-go/mapdecode.svg?branch=master
+[cov-img]: https://coveralls.io/repos/github/uber-go/mapdecode/badge.svg?branch=master
+[ci]: https://travis-ci.org/uber-go/mapdecode
+[cov]: https://coveralls.io/github/uber-go/mapdecode?branch=master