Add instructions on using Docker build

demo-shell-ng2/README.md

@@ -16,6 +16,7 @@
 Docker machine with latest `platform-distribution:api-latest` image.
 
 ```
+# docker-login is only needed the first time; after this your credentials will be cached
 docker login dockerreg.alfresco.com
 docker pull dockerreg.alfresco.com/platform-distribution:api-latest
 docker-compose up
@@ -28,7 +29,17 @@ to clean up afterwards
 docker-compose rm
 ```
 
-### Building and running steps:
+If you are using the local build you must also have configured your npm to use our private registry, where the
+components are published. Currently the registry can only be accessed from Alfresco's London and Maidenhead offices.
+
+    npm set registry http://devproducts.alfresco.me:4873
+
+Note this is a global setting which will apply to all your npm projects. You can use `npm config delete registry` to
+remove the setting once you no longer need it, or you can temporarily comment out the line in your `.npmrc` file.
+
+### Building and running
+
+#### Local build
 
 1 Install dependencies
 
@@ -46,6 +57,22 @@ npm start
 TypeScript watchers are also configured for `node_modules` folder within demo shell
 and provide live reload for all the component libraries as well.
 
+#### Docker build
+
+A Dockerfile is provided as part of the demo-shell. This can be used to build a local image using the current code
+that you have in your development environment. The `node_modules` folder will not be copied over, instead `npm install`
+is executed during the build to bring in the required dependencies from the registry, which ensures that you start from
+a clean base.
+
+Another advantage is that you do not need to have Node and npm installed locally, since these are already included with the
+base image.
+
+    docker build -t demo-shell --rm .
+    docker run -it --rm --name demo-shell-ng2 -p 3000 demo-shell
+
+When you are done testing you can remove the image that you created
+
+    docker rmi demo-shell
 
 ###Multi-language
 To support a new language you need to create your language file (.json) and add it to `i18n/` folder.