mailru: add Mail.Ru OAuth2 endpoint

Mail.Ru is one of the most popular email service provider in Russia.

The documentation for Mail.Ru's OAuth2 endpoints is at
https://o2.mail.ru/docs/

Change-Id: I605979b85cff2b00c7b65bbd3306d3fa66faa56d
Reviewed-on: https://go-review.googlesource.com/84415
Reviewed-by: Brad Fitzpatrick <[email protected]>

Author: narqo

mailru/mailru.go

@@ -0,0 +1,16 @@
+// 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 mailru provides constants for using OAuth2 to access Mail.Ru.
+package mailru // import "golang.org/x/oauth2/mailru"
+
+import (
+	"golang.org/x/oauth2"
+)
+
+// Endpoint is Mail.Ru's OAuth 2.0 endpoint.
+var Endpoint = oauth2.Endpoint{
+	AuthURL:  "https://o2.mail.ru/login",
+	TokenURL: "https://o2.mail.ru/token",
+}