Move deployment documentation to its own section

Signed-off-by: Tim Hansen <timbonicus@gmail.com>

docs/deployment/heroku.md

@@ -0,0 +1,44 @@
+---
+id: heroku
+title: Deploying with Heroku
+sidebar_label: Heroku
+description: How to deploy Backstage to Heroku
+---
+
+Heroku is a Platform as a Service (PaaS) designed to handle application
+deployment in a hands-off way. Heroku supports container deployment of Docker
+images, a natural fit for Backstage.
+
+## Configuring the CLI
+
+First, install the
+[heroku-cli](https://devcenter.heroku.com/articles/heroku-cli) and login:
+
+```shell
+$ heroku login
+```
+
+Heroku runs a container registry on `registry.heroku.com`. To push Backstage
+Docker images, log in to the container registry also:
+
+```shell
+$ heroku container:login
+```
+
+You _might_ also need to set your Heroku app's stack to `container`:
+
+```bash
+$ heroku stack:set container -a <your-app>
+```
+
+## Push and deploy a Docker image
+
+Now we can push a Backstage [Docker image](docker.md) to Heroku's container
+registry and release it to the `web` worker:
+
+```bash
+$ heroku container:push web -a <your-app>
+$ heroku container:release web -a <your-app>
+```
+
+Now you should have Backstage up and running! 🎉