add simplest possible express server to host files

...this is much better for development, so you can run many different servers
that have different HTML 5 local storages for testing purposes.

README.md

@@ -7,11 +7,23 @@ Copy config.template.js to config.js and edit to suit your needs. (Defaults to
 public PeerJS and Insight servers)
 
 Then execute these commands:
-
 ```
 npm install
 bower install
 grunt --target=dev shell
+node app.js
 ```
 
-Then open index.html in your browser.
+To run on a different port:
+```
+PORT=3001 node app.js
+```
+
+To open up five different instances to test 3-of-5 multisig with yourself, then run this in 5 different terminals:
+```
+PORT=3001 node app.js
+PORT=3002 node app.js
+PORT=3003 node app.js
+PORT=3004 node app.js
+PORT=3005 node app.js
+```