Update README.md

added running locally

README.md

@@ -11,3 +11,9 @@ You can test out your own copy of this right now on heroku by clicking this butt
 This will launch the Heroku installer console. You will be asked to enter a name for your app (we need this twice) - something like "CallFred" is good.
 It will also ask you to enter the number where you want callers to be connected to. Enter your number in international format without the + eg `447790900123`
 It will also ask you for your Nexmo API Key and Secret and finally it will ask you to enter a country where you would like to purchase a nexmo number, For this demo the number is only used for the Caller ID.
+
+
+## Running Locally
+If you wish to run the application locally you can download this repo, edit the `EXAMPLE.env` file to contain your details and rename to `.env` then add your nexmo appliaciton private key to a file called `private.key`.
+Install the requirements using `pip -r requirements.txt` and launch the app by running `python app.py` 
+The app will launch by default on port 5000