Updated Client compatibility list (markdown)

Client-compatibility-list.md

@@ -36,6 +36,17 @@ var s3 = new AWS.S3({
 
 Also specify `jclouds.regions = us-east-1` to work around [aws/aws-sdk-js#919](https://github.com/aws/aws-sdk-js/issues/919).
 
+### [AWS SDK for Ruby](https://github.com/aws/aws-sdk-ruby)
+
+```ruby
+require 'aws-sdk'
+
+Aws.config.update({
+    credentials: Aws::Credentials.new('identity', 'credential'),
+    endpoint: 'http://localhost:8081'
+})
+```
+
 ### [boto](https://github.com/boto/boto)
 
 ```python