Update README.md

Author: briangonzalez

README.md

@@ -64,6 +64,8 @@ Caveats
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 This plugin utlizes the `<canvas>` element and the `ImageData` object, and due to cross-site security limitations, the script will fail if one tries to extract the colors from an image not hosted on the current domain, *unless* the image allows for [Cross Origin Resource Sharing](http://en.wikipedia.org/wiki/Cross-origin_resource_sharing). 
 
+__Enabling CORS on S3__
+
 To enable CORS for images hosted on S3 buckets, follow the Amazon guide [here](http://docs.aws.amazon.com/AmazonS3/latest/UG/EditingBucketPermissions.html); adding the following to the bucket's CORS configuration:
 
 ```xml