Update README.md

Author: bvanvugt

README.md

@@ -1,2 +1,19 @@
 # action-version-release
-GitHub Action to write VERSION.txt and include it in each release.
+Simple GitHub Action to write VERSION.txt and include it in each release. Note this force updates the release tag, such that the tagged commit contains the new VERSION.txt file.
+
+## Usage
+```yaml
+name: Release
+
+on:
+  release:
+    types: [published]
+    branches: [main]
+
+jobs:
+  version:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: BattlesnakeOfficial/action-version-txt@v1
+```