docs(readme): add module usage

package.json

@@ -5,6 +5,7 @@
   "description": "Generate a table of contents for a GitHub discussion",
   "author": "Gregor Martynus (https://github.com/gr2m)",
   "license": "ISC",
+  "repository": "github:gr2m/github-discussion-toc",
   "dependencies": {
     "octokit": "^3.1.0"
   },

readme.md

@@ -4,14 +4,30 @@ A script to generate a table of contents for a GitHub discussion.
 
 The script finds all comments that begin with a level 3 heading (`### My heading`) and adds a table of contents with links to those headings to the top of the discussion.
 
-## Usage
+## CLI Usage
 
 You need a [GitHub personal access token](https://github.com/settings/tokens/new?scopes=public_repo&description=github-discussion-toc) with the `public_repo` scope for public repositories or the `repo` scope for private repositories.
 
 ```
 GITHUB_TOKEN="<personal access token>" npx github-discussion-toc <discussion-url>
 ```
 
+## Module usage
+
+```js
+import addTocToGitHubDiscussion from "github-discussion-toc";
+import { Octokit } from "octokit";
+
+const myOctokit = new Octokit({
+  auth: process.env.GITHUB_TOKEN,
+});
+const myOwner = "octocat";
+const myRepo = "hello-world";
+const myDiscussionNumber = 123;
+
+await addTocToGitHubDiscussion(myOctokit, myOwner, myRepo, myDiscussionNumber);
+```
+
 ## License
 
 [ISC](license.md)