Added a section about picking a name for the Heroku app

Thanks to pozorvlak for the feedback and original proposal.

deploy/README.md

@@ -150,17 +150,33 @@ Next, we’ll create a new git repository and save our changes. Go to your conso
      create mode 100644 requirements.txt
      create mode 100644 runtime.txt
 
-## Deploy to Heroku!
+## Pick an application name
 
-That was a lot of configuration and installing, right? But you only need to do that once! Now you can deploy!
+We'll be making your blog available on the Web at `[your blog's name].herokuapp.com`, so we need to choose a name that nobody else has taken. This name doesn't need to be related to the Django `blog` app or to `mysite` or anything we've created so far. The name can be anything you want, but Heroku is quite strict as to what characters you can use: you're only allowed to use simple lowercase letters (no capital letters or accents), numbers, and dashes (`-`).
 
-It's as simple as running this command, replacing `djangogirlsblog` with your own application name:
+Once you've thought of a name (maybe something with your name or nickname in it), run this command, replacing `djangogirlsblog` with your own application name:
 
     $ heroku create djangogirlsblog
 
 > __Note__: Remember to replace `djangogirlsblog` with the name of your application on Heroku.
 
-This automatically added the Heroku remote for our app to our repository. Now we can do a simple git push to deploy our application:
+If you can't think of a name, you can instead run
+
+    $ heroku create
+
+and Heroku will pick an unused name for you (probably something like `enigmatic-cove-2527`).
+
+If you ever feel like changing the name of your Heroku application, you can do so at any time with this command (replace `the-new-name` with the new name you want to use):
+
+    $ heroku apps:rename the-new-name
+
+> __Note__: Remember that after you change your application's name, you'll need to visit `[the new name].herokuapp.com` to see your site.
+
+## Deploy to Heroku!
+
+That was a lot of configuration and installing, right? But you only need to do that once! Now you can deploy!
+
+When you ran `heroku create`, it automatically added the Heroku remote for our app to our repository. Now we can do a simple git push to deploy our application:
 
     $ git push heroku master