clarified extension registry, fixes issue spree#48

source/creating_extensions.textile

@@ -128,6 +128,10 @@ s.required_ruby_version = '>= 1.8.7'
 # s.rubyforge_project = 'actionmailer'
 </ruby>
 
+h4. Registering Your Extension
+
+In order for your extension to show up in the "Extension Registry":http://spreecommerce.com/extensions you need to register it. To do so, sign into your spreecommerce.com account and navigate to the "My Extensions":http://spreecommerce.com/account/extensions page. You may have to create an account first, or you can log-in with GitHub.
+
 h3. Versionfile
 
 Spree is moving at a rapid pace with the code constantly evolving as new releases are being pushed out.  These changes sometimes make it difficult to keep track of which version of Spree is compatible with which version of an extension. To solve this problem extension authors are encouraged to add a +Versionfile+ to their extension.