docs: add heroku deployment information (#126)

docs/deploy/providers/heroku.md

@@ -2,6 +2,24 @@
 
 **Preset:** `heroku` ([switch to this preset](/deploy/#changing-the-deployment-preset))
 
-::: warning Work in Progress
-Documentation for this section is not yet complete.
-:::
+Nitro supports deploying on [Heroku](https://heroku.com/) with minimal configuration.
+
+## Using the Heroku CLI
+
+1. Create a new Heroku app.
+
+   ```bash
+   heroku create myapp
+   ```
+
+1. Configure Heroku to use the nodejs buildpack.
+
+   ```bash
+   heroku buildpacks:set heroku/nodejs
+   ```
+
+1. Configure your app.
+
+   ```bash
+   heroku config:set NITRO_PRESET=heroku
+   ```