added variable packaging_repositories to documentation

README.md

@@ -9,9 +9,18 @@ Requirements
 Variables
 ----------
 
-- development note: Define these variables in the defaults/main.yml file of your sub-role.
-
-    
+development note: Define these variables in the defaults/main.yml or vars/main.yml file of your sub-role.
+
+packaging_repositories:
+  * description:
+    * This is a list of dictionaries for the reporsitories of a package management and contains some information about them.
+    * Every list entry has following keys by default:
+      - name: name of the repository as string
+      - url: URL of the repository as string
+      - enabled: activation state of the repository as boolean
+    * The keys of each entry can be extended depending on the package manangement.
+  * default: []
+     
 Processes
 =========