add systemjs paths key clarification

Author: filipesilva

public/docs/_examples/production-deploy/ts/systemjs.config.server.js

@@ -6,9 +6,11 @@
  */
 (function (global) {
   System.config({
+    // #docregion paths
     paths: {
       'npm:': 'https://unpkg.com/' // path serves as alias
     },
+    // #enddocregion paths
     // map tells the System loader where to look for things
     map: {
       app: 'app', // location of transpiled app files

public/docs/ts/latest/guide/production-deploy.jade

@@ -66,7 +66,20 @@ a#toc
   (3) Add `systemjs.config.server.js` (shown in the code sample below) to your root folder.
   This alternative version configures _SystemJS_ to load _UMD_ versions of Angular 
   (and other third-party packages) from the web.
-  Modify it as necessary to stay in sync with changes you make to `systemjs.config.js`.
+
+  Pay special attention to the `paths` key:
+
++makeExample('systemjs.config.server.js', 'paths', '')(format=".")
+
+:marked
+  In your usual SystemJS config the `npm` path points at your local `node_modules/`,
+  but on the server config it points at https://unpkg.com/ - a site that hosts NPM packages.
+
+  This way you can load your node modules from the internet directly. 
+  You can use any other provider you which, as long as it serves the needed files.
+
+  Modify `systemjs.config.server.js` as necessary to stay in sync with changes
+  you make to `systemjs.config.js`.
 
   The following trivial router sample app shows these changes.