git-rebase: add --onto option (#1080)

pages/common/git-rebase.md

@@ -6,7 +6,7 @@
 
 `git rebase -i master`
 
-- Rebase your local branch  interactively with the latest changes from upstream:
+- Rebase your local branch interactively with the latest changes from upstream:
 
 `git fetch origin; git rebase -i origin/master`
 
@@ -17,3 +17,7 @@
 - Abort a rebase in-progress:
 
 `git rebase --abort`
+
+- Rebase your local branch by specifying new base commit and old base commit:
+
+`git rebase --onto {{new_base_commit}} {{old_base_commit}}`