Added backlink to github to the documentation

Author: moay

docs/index.md

@@ -1,6 +1,9 @@
 # symfony-flex-server
+
 A self hosted server for Symfony Flex allowing private recipes, customized recipes and caching functionality for the official endpoints.
 
+[github.com/moay/symfony-flex-server](https://github.com/moay/symfony-flex-server)
+
 ![ui](https://user-images.githubusercontent.com/3605512/36627099-eb239f48-193d-11e8-919a-d98003696d7b.png)
 
 ### Features