Updating README to include stack deploy instructions

Author: ManoMarks

README.md

@@ -4,14 +4,23 @@ Instavote
 Getting started
 ---------------
 
-Download [Docker for Mac or Windows](https://www.docker.com).
+Download [Docker](https://www.docker.com/products/overview). If you are on Mac or Windows, [Docker Compose](https://docs.docker.com/compose) will be automatically installed. On Linux, make sure you have the latest version of [Compose](https://docs.docker.com/compose/install/).
 
 Run in this directory:
-
-    $ docker-compose up
-
+```
+docker-compose up
+```
 The app will be running at [http://localhost:5000](http://localhost:5000), and the results will be at [http://localhost:5001](http://localhost:5001).
 
+Alternately, if you want to run it on a [Docker Swarm](https://docs.docker.com/engine/swarm/), first make sure you have a Swarm. If you don't, run:
+```
+docker swarm init
+```
+Once you have your swarm, in this directory run:
+```
+docker stack deploy --compose-file docker-stack.yml vote
+```
+
 Architecture
 -----