first pass at an Antora conversion

preview.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+
+if [ "$(uname)" == "Darwin" ]; then
+    # Running on macOS.
+    # Let's assume that the user has the Docker CE installed
+    # which doesn't require a root password.
+    echo "The preview will be available at http://localhost:8080/"
+    docker run --rm -v $(pwd):/antora:ro -v $(pwd)/nginx.conf:/etc/nginx/conf.d/default.conf:ro -p 8080:80 nginx
+
+elif [ "$(expr substr $(uname -s) 1 5)" == "Linux" ]; then
+    # Running on Linux.
+    # Let's assume that it's running the Docker deamon
+    # which requires root.
+    echo ""
+    echo "This build script is using Docker to run the build in an isolated environment. You might be asked for a root password in order to start it."
+    echo "The preview will be available at http://localhost:8080/"
+    sudo docker run --rm -v $(pwd):/antora:ro,z -v $(pwd)/nginx.conf:/etc/nginx/conf.d/default.conf:ro,z -p 8080:80 nginx
+fi