Add README

Author: mheap

README.md

@@ -0,0 +1,30 @@
+# Heroku Build Logs
+
+Attach Heroku build logs on deployment failure
+
+## Usage
+
+```yaml
+name: Heroku Build Logs
+on: deployment_status
+
+jobs:
+  heroku-build-logs:
+    name: Heroku Build Logs
+    runs-on: ubuntu-latest
+    steps:
+      - name: Heroku Build Logs
+        uses: mheap/github-action-heroku-logs@master
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          HEROKU_AUTH_TOKEN: ${{ secrets.HEROKU_AUTH_TOKEN }}
+```
+
+## Available Configuration
+
+### Environment Variables
+
+| Name              | Description                                                                                                       |
+| ----------------- | ----------------------------------------------------------------------------------------------------------------- |
+| GITHUB_TOKEN      | The GitHub auth token, used to authenticate API requests. Use the value provided in `${{ secrets.GITHUB_TOKEN }}` |
+| HEROKU_AUTH_TOKEN | Your Heroku API key. Used to fetch build logs                                                                     |