Merge pull request #2 from twosigma/readme

Update README.md

README.md

@@ -1,17 +1,33 @@
-<p align="center">
-  <a href="https://github.com/actions/typescript-action/actions"><img alt="typescript-action status" src="https://github.com/actions/typescript-action/workflows/build-test/badge.svg"></a>
-</p>
+# maven-cache-cleaner
 
-# cache-maven
+![CI](https://github.com/twosigma/maven-cache-cleaner/actions/workflows/test.yml/badge.svg)
+[![Check dist/](https://github.com/twosigma/maven-cache-cleaner/actions/workflows/check-dist.yml/badge.svg)](https://github.com/actions/typescript-action/actions/workflows/check-dist.yml)
 
-This action properly caches your `~/.m2` repository to speed up your Maven builds. It also cleans up and only caches the dependencies in use to avoid infinite cache growth.
+This action cleans up all Maven dependencies not used after calling the cache cleaner action. It is intended to be used after `actions/cache` to clean up the cache right before saving it. It is intended to prevent the cache from growing infinitely large with dependencies that are no longer used.
+
+This action uses `atime` to determine if a dependency was used or not. If a dependency was not used, it will be deleted.
+
+The action cleaning mechanism is inspired by this [StackOverflow answer](https://stackoverflow.com/a/29970448).
+
+## Usage
+
+Add these near the top of the workflow:
+
+```yaml
+uses: actions/cache@v4
+with:
+  path: ~/.m2/repository
+  key: ${{ runner.os }}-maven-build # Or any other key you want
+uses: twosigma/maven-cache-cleaner@v1
+```
+
+Any files not accessed within the `~/.m2` directory after the `twosigma/maven-cache-cleaner` step will be deleted at the end of the action, before `actions/cache` saves the directory.
 
 ## Developer Guide
 
 ### Setup
 
 ```console
-$ dawn setup
 $ npm install
 ```
 
@@ -22,4 +38,3 @@ $ npm run all
 ```
 
 Make sure to run the above before committing changes, or the GitHub action will fail.
-