Add some of my hacking notes to the README

README.adoc

@@ -40,12 +40,30 @@ environment variables which can override configuration values.
 | `warn`
 | Log level for Contaminate logs to be printed
 
-| `CT_LAYERS_DIR`
+| `CT_layers_dir`
 | `./layers.d`
 | A directory containing the layers to override on images passing through Contaminate.
 
-| `CT_REGISTRY`
+| `CT_registry`
 | https://registry-1.docker.io
 | A Registry HTTP V2 compliant URL, reachable by Contaminate.
 
 |===
+
+== Hacking
+
+Ensure that your local Docker daemon can access your Contaminate instance
+without requiring HTTPs:
+
+./etc/sysconfig/docker
+[source, sh]
+----
+DOCKER_OPTS="--insecure-registry=localhost:5000 --insecure-registry=localhost:9090"
+----
+
+Running a local Docker registry to contaminate:
+
+[source, sh]
+----
+docker run --rm -ti -e REGISTRY_HTTP_SECRET=secret -p 5000:5000 registry:2
+----