README: add Build Status and Go Report Card links

README.md

@@ -1,4 +1,5 @@
 # SFTPGo
+[![Build Status](https://travis-ci.org/drakkan/sftpgo.svg?branch=master)](https://travis-ci.org/drakkan/sftpgo) [![Go Report Card](https://goreportcard.com/badge/github.com/drakkan/sftpgo)](https://goreportcard.com/report/github.com/drakkan/sftpgo)
 
 Full featured and highly configurable SFTP server software