Merge pull request #1427 from dungeonmaster18/go-report-card-badge

Added goreportcard badge to readme file.

README.md

@@ -4,6 +4,7 @@
   <a href="https://ci.appveyor.com/project/golang/dep"><img src="https://ci.appveyor.com/api/projects/status/github/golang/dep?svg=true&branch=master&passingText=Windows%20-%20OK&failingText=Windows%20-%20failed&pendingText=Windows%20-%20pending" alt="Windows Build Status"></a>
   <a href="https://codeclimate.com/github/golang/dep"><img src="https://codeclimate.com/github/golang/dep/badges/gpa.svg" alt="Code Climate"></img></a>
   <a href="https://codeclimate.com/github/golang/dep/coverage"><img src="https://codeclimate.com/github/golang/dep/badges/coverage.svg" /></a>
+  <a href="https://goreportcard.com/report/github.com/golang/dep"><img src="https://goreportcard.com/badge/github.com/golang/dep" /></a>
 </p>
 
 ## Dep