diff --git a/LICENSE b/LICENSE
index f1b3852..74f75fa 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2021 谭九鼎
+Copyright (c) 2021 IMBA-TJD
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/Readme.md b/Readme.md
new file mode 100644
index 0000000..09ba584
--- /dev/null
+++ b/Readme.md
@@ -0,0 +1,43 @@
+# Rebase Upstream Action
+
+This Action is suitable if you:
+
+* are maintaining a fork
+* have changes that are not going to be merged into upstream
+* want to keep changes based on the latest upstream
+
+Basically this is doing `git rebase upstream master`. If there are conflicts, it simply fails.
+
+## Typical usage
+
+```yml
+# .github/workflows/sync.yml
+name: Rebase Upstream
+on:
+  schedule:
+  - cron: "0 0 * * *"
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@master
+      with:
+        fetch-depth: 10  # larger than the number of commits you made
+    - uses: imba-tjd/rebase-upstream-action@master
+      id: rebase
+      with:
+        upstream: https://github.com/<user>/<repo>.git
+    - uses: ad-m/github-push-action@master
+      if: steps.rebase.outputs.needs-push
+      with:
+        force: true
+        github_token: ${{ github.token }}
+```
+
+## Comparison
+
+* tgymnich/fork-sync and apps/pull: I don't want PRs. Besides there is not way to do a `git rebase` on GitHub website
+* repo-sync/github-sync: It's not using rebase or merge. It completely mirrors the upstream. And it can't sync current branch
+* wei/git-sync: Very complicated and have the same issue as github-sync. After all its aim is "syncing between two independent repo"
+* This one: Not widely tested. Use with caution
diff --git a/action.yml b/action.yml
new file mode 100644
index 0000000..a8d55c7
--- /dev/null
+++ b/action.yml
@@ -0,0 +1,46 @@
+name: Rebase Upstream
+description: Use git rebase to sync with upstream
+author: imba-tjd
+branding:
+  icon: git-pull-request
+  color: red
+
+inputs:
+  upstream:
+    description: The full HTTPS upstream URL.
+    required: true
+  branch:
+    description: The upstream branch that is rebased on.
+    required: false
+    default: master
+  depth:
+    description: The fetch depth
+    required: false
+    default: 100
+outputs:
+  needs-push:
+    description: Whether push is needed.
+    value: ${{ steps.set-output.outputs.needs-push }}
+runs:
+  using: composite
+  steps:
+    - run: |
+        echo adding ${{ inputs.upstream }} && \
+        git remote add upstream ${{ inputs.upstream }};
+
+        echo fetching... && \
+        git fetch upstream --depth=${{ inputs.depth }};
+
+        git config --local user.email "41898282+github-actions[bot]@users.noreply.github.com";
+        git config --local user.name "GitHub Action";
+
+        echo rebasing... && \
+        git rebase upstream/${{ inputs.branch }};
+      shell: bash
+    - id: set-output
+      shell: bash
+      run: |
+        if [ "$(git status | grep diverged)" ]; then
+          echo push is needed.
+          echo ::set-output name=needs-push::1
+        fi;