From cd2e0cf3f12bd0da31c3643e09ec13a6f14d37a7 Mon Sep 17 00:00:00 2001
From: Shiyason <yan@shiyason.com>
Date: Fri, 13 Jul 2018 04:20:30 +0900
Subject: [PATCH] Update README.md (#141)

Add instructions for environment variables.
---
 README.md | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/README.md b/README.md
index b6a4462..bad2061 100644
--- a/README.md
+++ b/README.md
@@ -143,6 +143,15 @@ authorizer = Google::Auth::ServiceAccountCredentials.make_creds(
 authorizer.fetch_access_token!
 ```
 
+### Example (Environment Variables)
+
+```bash
+export GOOGLE_ACCOUNT_TYPE=service_account
+export GOOGLE_CLIENT_ID=000000000000000000000
+export GOOGLE_CLIENT_EMAIL=xxxx@xxxx.iam.gserviceaccount.com
+export GOOGLE_PRIVATE_KEY="-----BEGIN PRIVATE KEY-----\n...\n-----END PRIVATE KEY-----\n"
+```
+
 ### Storage
 
 Authorizers require a storage instance to manage long term persistence of