Docker/docker-compose enhancements

The following enhancements have been made to docker/docker-compose

* Fixed bug when building the image.
* docker-compose up starts the server
* Scaffolding inside the container respect the ownership of the files
outside it
* Volumes are tagged as 'delegated' in order to improve performance for
mac/windoze users.
* bundler stores packages in a volume. This whay new packages can be
added without rebuilding the image:

```bash
docker-compose run app bundle install
```

scripts/entrypoint.sh

@@ -0,0 +1,17 @@
+#!/bin/sh -x
+
+USER_UID=$(stat -c %u /var/www/consul/Gemfile)
+USER_GID=$(stat -c %g /var/www/consul/Gemfile)
+
+export USER_UID
+export USER_GID
+
+usermod -u "$USER_UID" consul 2> /dev/null
+groupmod -g "$USER_GID" consul 2> /dev/null
+usermod -g "$USER_GID" consul 2> /dev/null
+
+chown -R -h "$USER_UID" "$BUNDLE_PATH"
+chgrp -R -h "$USER_GID" "$BUNDLE_PATH"
+
+/usr/bin/sudo -EH -u consul "$@"
+