Updated Adding support for a new Mod (markdown)

Adding-support-for-a-new-Mod.md

@@ -10,7 +10,12 @@ Crafting Guide comes with a number of different command-line scripts for process
 
 Start by checking to see if you already have Node.js or Ruby installed on your machine by running the following commands: `which node` and `which ruby`.  If you have them installed, you'll see where they're installed.  If you don't have them, then there will be no output.  If either is missing, download and install the most recent version of each from their websites: [Node.js](http://nodejs.org/download/) and [Ruby](https://ruby-lang.org).  
 
-Next, open a terminal and navigate to your new local repo.  Run the following commands to get the rest of the tools you need and build everything locally.
+Next, open a terminal and navigate to your new local repo.  Create a file called `.env` with the following contents:
+```
+WEBSITE_SERVER_PORT=8080
+```
+
+Finally, run the following commands to get the rest of the tools you need and build everything locally.
 ```bash
 sudo npm install -g browserify
 sudo npm install -g coffee-script