Added build instructions for installing the NPM modules for React and…

… React DOM.

BUILD_INSTRUCTIONS

@@ -44,7 +44,21 @@
     ...
 
 
-(8) Bundle / transpile the JavaScript with Webpack for deployment:
+(8) Install the NPM module for React:
+
+    $ npm install react
+
+    ...
+
+
+(9) Install the NPM module for React DOM:
+
+    $ npm install react-dom
+
+    ...
+
+
+(10) Bundle / transpile the JavaScript with Webpack for deployment:
 
     $ ./node_modules/webpack/bin/webpack.js --config ./webpack.config.js