Add favicon.ico and handler

Created a goreportcard favicon based on the original
https://golang.org/favicon.ico gopher favicon.

handlers/assets.go

@@ -10,3 +10,9 @@ func AssetsHandler(w http.ResponseWriter, r *http.Request) {
 	log.Println("Serving " + r.URL.Path[1:])
 	http.ServeFile(w, r, r.URL.Path[1:])
 }
+
+// FaviconHandler handles serving the favicon.ico
+func FaviconHandler(w http.ResponseWriter, r *http.Request) {
+	log.Println("Serving " + r.URL.Path[1:])
+	http.ServeFile(w, r, "assets/favicon.ico")
+}

main.go

@@ -81,6 +81,7 @@ func main() {
 	}
 
 	http.HandleFunc("/assets/", handlers.AssetsHandler)
+	http.HandleFunc("/favicon.ico", handlers.FaviconHandler)
 	http.HandleFunc("/checks", handlers.CheckHandler)
 	http.HandleFunc("/report/", makeHandler("report", handlers.ReportHandler))
 	http.HandleFunc("/badge/", makeHandler("badge", handlers.BadgeHandler))