add arch linux support

main.go

@@ -87,6 +87,12 @@ func main() {
 		CertBase = "/etc/ssl/certs"
 		KeyBase = "/etc/ssl/private"
 		GroupName = "ssl-cert"
+	} else if OSRelease == "arch" {
+		CertBase = "/etc/ssl/certs"
+		KeyBase = "/etc/ssl/private"
+		GroupName = "root"
+	} else {
+		log.Fatalf("don't know what to do with OS: %v", OSRelease)
 	}
 
 	usage := fmt.Sprintf(`ACME Downloader: