Add Terraform Registry badge (closes #2)

Author: jbeemster

README.md

@@ -1,4 +1,4 @@
-[![Release][release-image]][release] [![CI][ci-image]][ci] [![License][license-image]][license]
+[![Release][release-image]][release] [![CI][ci-image]][ci] [![License][license-image]][license] [![Registry][registry-image]][registry]
 
 # terraform-aws-postgres-loader-kinesis-ec2
 
@@ -276,3 +276,6 @@ limitations under the License.
 
 [license]: https://www.apache.org/licenses/LICENSE-2.0
 [license-image]: https://img.shields.io/badge/license-Apache--2-blue.svg?style=flat
+
+[registry]: https://registry.terraform.io/modules/snowplow-devops/postgres-loader-kinesis-ec2/aws/latest
+[registry-image]: https://img.shields.io/static/v1?label=Terraform&message=Registry&color=7B42BC&logo=terraform