leighmcculloch: add a first contribution

What
===
Add a first contribution to the scratch repo.

Why
===
Because I want to contribute to Go and I'm in the GopherCon Go
Contributor Workshop!

Change-Id: Iffd46054cc6ca993d71e8572d37f3d505380ccd9
Reviewed-on: https://go-review.googlesource.com/48814
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

leighmcculloch/main.go

@@ -0,0 +1,12 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("HI! This is my first contribution to a googlesource repo using gerrit.")
+	fmt.Println("╰(◕ヮ◕)つ¤=[]———")
+}