More Docker work

- Dockerfile now builds Inbucket inside the container
- Add starter inbucket.conf for Docker
- Add install.sh to build inbucket inside container
- Add customized greeting.html for Docker

docker-run.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+# docker-run.sh
+# description: Launch Inbucket's docker image
+
+if [ "$UID" -ne 0 ]; then
+  sudo $0 "$@"
+fi
+
+docker run -p 9000:10080 -p 2500:10025 -p 1100:10110 jhillyerd/inbucket