docs: update instructions

README.md

@@ -2,5 +2,26 @@
 
 > A preview service for freeCodeCamp.org news for posts on Hashnode (headless) CMS.
 
-This uses Hashnode's GraphQL API and Nunjucks to render an approximate preview of a post as it will appear when published live on `/news`, which uses Eleventy and Nunjucks.
+This uses Hashnode's GraphQL API and Nunjucks to render an approximate preview
+of a post as it will appear when published live on `/news`.
 
+## Usage
+
+- The app is deployed on DigitalOcean App Platform, and all changes merged to
+  the `main` branch are deployed using the
+  [`deploy.yml`](.github/workflows/deploy.yml) workflow.
+
+- Alternatively, you can run the app using the included `docker-compose.yml` file.
+
+  ```bash
+  docker compose build
+  docker compose up -d
+  ```
+
+> [!NOTE]
+> Need to set the following environment variables
+
+**Environment Variables**
+
+- `CMS_HOST`: The Hashnode Publication URL
+- `PORT`: The port to run the server on