docs: Add inputs, workflow example

Author: nickderobertis

README.md

@@ -1,15 +1,60 @@
 # Github Topic Syncer
 
-Sync Github Topics from a Github Action
+Sync Github Topics from a Github Action.
+
+Whatever topics are provided in the action will replace the topics in the Github repository
+when the action is executed.
 
 ## Inputs
 
+## `topics`
+
+A space-separated list of topics to sync. Topics can only contain lower-case letters,
+numbers, and hyphens.
+
+### Examples
+
+```yaml
+with:
+  topics: "web-development python"
+```
+
+## `token`
 
-## Outputs
+A Github personal access token with the `repo` scope. Typically this is stored
+in repository secrets to provide to the action:
 
+### Examples
+
+```yaml
+with:
+  token: ${{ secrets.gh_token }}
+```
 
 ## Examples
 
+Here's an example workflow that syncs the topics of a Github repository whenever
+the workflow is updated on the `main` branch.
+
+```yaml
+name: Sync Github Topics
+on:
+  push:
+    paths:
+      - ".github/workflows/sync-topics.yml"
+    branches:
+      - main
+
+jobs:
+  sync-topics:
+    runs-on: ubuntu-latest
+    name: Sync Github Topics
+    steps:
+      - uses: nickderobertis/github-topic-syncer@alpha
+        with:
+          topics: "topic1 topic-2"
+          token: ${{ secrets.gh_token }}
+```
 
 ## Development Status
 
@@ -18,11 +63,10 @@ Any time the major version changes, there may be breaking changes. If it is work
 pegging to the current major version, e.g. `github-topic-syncer@v1`, to avoid breaking changes. Alternatively,
 you can always point to the most recent stable release with the `github-topic-syncer@latest`.
 
-
 ## Developing
 
 Clone the repo and then run `npm install` to set up the pre-commit hooks.
 
 ## Author
 
-Created by Nick DeRobertis. MIT License.
+Created by Nick DeRobertis. MIT License.