update readme

Dockerfile

@@ -5,7 +5,6 @@ LABEL "com.github.actions.description"="This action deploys your AWS Amplify pul
 LABEL "com.github.actions.icon"="git-commit"
 LABEL "com.github.actions.color"="blue"
 
-LABEL version="0.2"
 LABEL "repository"="https://github.com/yinlinchen/amplify-preview-actions.git"
 LABEL "homepage"="https://github.com/yinlinchen/amplify-preview-actions"
 LABEL maintainer="Yinlin Chen <[email protected]>"

README.md

@@ -1,2 +1,45 @@
 # amplify-preview-actions
 
+[![RELEASE](https://img.shields.io/github/v/release/yinlinchen/amplify-preview-actions?include_prereleases)](https://github.com/ambientlight/amplify-cli-action/releases)
+[![LICENSE](https://img.shields.io/github/license/yinlinchen/amplify-preview-actions)](https://github.com/yinlinchen/amplify-preview-actions/blob/master/LICENSE)
+[![ISSUES](https://img.shields.io/github/issues/yinlinchen/amplify-preview-actions)](https://github.com/yinlinchen/amplify-preview-actions/issues)
+
+AWS Amplify pull request preview currently only supports private github repositoy. This action deploys your AWS Amplify pull request preview for your public repository.
+
+## Getting Started
+You can include the action in your workflow as `actions/[email protected]`.
+
+Example:
+
+```yaml
+name: 'Amplify PR Preview'
+on:
+  pull_request:
+    types: [review_requested]
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@master
+
+    - name: set branchname env
+      id: setenvname
+      run: |
+        # use GITHUB_HEAD_REF that is set to PR source branch
+        # also remove -_ from branch name and limit length to 10 for amplify env restriction
+        echo "##[set-output name=setbranchname;]$(echo ${GITHUB_HEAD_REF//[-_]/} | cut -c-10)"
+
+    - name: deploy PR preview
+      uses: yinlinchen/[email protected]
+      with:
+        branch_name: ${{ steps.setenvname.outputs.setbranchname }}
+        aws_cli_version: '1.18.135'
+      env:
+        AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
+        AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
+        AmplifyAppId: ${{ secrets.AmplifyAppId }}
+        BackendEnvARN: ${{ secrets.BackendEnvARN }}
+        AWS_REGION: 'us-east-1'
+```
+