docs: add godocs link

Author: antonfisher

.gitignore

@@ -10,3 +10,6 @@
 
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
+
+# IDE
+*.code-workspace

README.md

@@ -2,6 +2,7 @@
 
 [![Build Status](https://travis-ci.org/antonfisher/nested-logrus-formatter.svg?branch=master)](https://travis-ci.org/antonfisher/nested-logrus-formatter)
 [![Go Report Card](https://goreportcard.com/badge/github.com/antonfisher/nested-logrus-formatter)](https://goreportcard.com/report/github.com/antonfisher/nested-logrus-formatter)
+[![GoDoc](https://godoc.org/github.com/antonfisher/nested-logrus-formatter?status.svg)](https://godoc.org/github.com/antonfisher/nested-logrus-formatter)
 
 Human-readable log formatter, converts _logrus_ fields to a nested structure: