Update local.md

docs/cozystack/local.md

@@ -18,6 +18,17 @@ That's why we took the shortcut of using an official [CouchDB image](https://hub
 
 ## How to build new version of the stack ?
 
+Be sure to have a local version of the projet. Manually add a new remote origin https://github.com/cozy/cozy-stack named cozy. 
+
+Run the following commands :
+
+```bash
+git pull cozy master
+git push origin master
+```
+
+Then rebase the `feat/stack-pipeline` with last changes form master.
+
 If we want to build a new stack version it's easy! A manual pipeline has been created. You just need to run the following steps:
 
 * Run the manual pipeline attached to our gitlab CI/CD