update readme

README.md

@@ -1,7 +1,7 @@
 # About aws-s3
 
 This module allows you to create an S3 bucket, either a standard bucket or a bucket used for FTI (Title26)
-data.
+data.  You can also create a KMS key to be used by a bucket.
 
 This was formerly named `aws-t26-s3`.
 
@@ -29,4 +29,15 @@ module "mybucket" {
 }
 ```
 
+* [KMS Key](kms_key)
+
+```hcl
+module "simple-key" {
+  source   = "git@github.e.it.census.gov:terraform-modules/aws-s3.git//kms_key"
+  key_name = "my-simple-key"
+}
+```
+
 See each section for additional information.
+
+