Clarify creating a new plugin as the next step (#575)

* Move create-app docs out from getting started

* Add contributing to readme.md

docs/create-an-app.md

@@ -17,7 +17,7 @@ npx @backstage/cli create-app
 This will create a new Backstage App inside the current folder. The name of the app-folder is the name that was provided when prompted.
 
 <p align='center'>
-    <img src='https://github.com/spotify/backstage/raw/master/docs/getting-started/create-app_output.png' width='600' alt='create app'>
+    <img src='https://github.com/spotify/backstage/raw/master/docs/create-app_output.png' width='600' alt='create app'>
 </p>
 
 Inside that directory, it will generate all the files and folder structure needed for you to run your app.
@@ -70,7 +70,3 @@ yarn start
 ```
 
 _When `yarn start` is ready it should open up a browser window displaying your app, if not you can navigate to `http://localhost:3000`._
-
-[Next Step - Create a Backstage plugin](create-a-plugin.md)
-
-[Back to Docs](README.md)

docs/getting-started/README.md

@@ -1,9 +1,10 @@
 # Getting started with Backstage
 
-Here is a collection of tutorials that will guide you through setting up and extending an instance of Backstage with your own plugins.
+## Creating a Plugin
+
+The value of Backstage grows with every new plugin that gets added. Here is a collection of tutorials that will guide you through setting up and extending an instance of Backstage with your own plugins.
 
 - [Development Environment](development-environment.md)
-- [Create a Backstage App](create-an-app.md)
 - [Create a Backstage plugin](create-a-plugin.md)
 - [Structure of a plugin](structure-of-a-plugin.md)
 - Using Backstage components (TODO)

docs/getting-started/development-environment.md

@@ -34,4 +34,6 @@ Then open http://localhost/ on your browser.
 
 > See [package.json](/package.json) for other yarn commands/options.
 
+[Next Step - Create a Backstage plugin](create-a-plugin.md)
+
 [Back to Docs](README.md)