Update start-using-git.md

doc/gitlab-basics/start-using-git.md

@@ -120,3 +120,11 @@ You need to be in the created branch.
 git checkout NAME-OF-BRANCH
 git merge master
 ```
+
+### Merge master branch with created branch
+You need to be in the master branch.
+```
+git checkout master
+git merge NAME-OF-BRANCH
+```
+