Document Buildkite Tart Plugin (#677)

* Document Buildkite Tart Plugin

* Fix cropped screenshot

docs/integrations/buildkite.md

@@ -0,0 +1,21 @@
+# Buildkite
+
+It is possible to run [Buildkite](https://buildkite.com/) pipeline steps in isolated ephemeral Tart Virtual Machines with the help of [Tart Buildkite Plugin](https://github.com/cirruslabs/tart-buildkite-plugin):
+
+![](/assets/images/BuildkiteTartPlugin.png)
+
+## Configuration
+
+The most basic configuration looks like this:
+
+```yaml
+steps:
+- command: uname -a
+  plugins:
+  - cirruslabs/tart#main:
+    image: ghcr.io/cirruslabs/macos-sonoma-base:latest
+```
+
+This will run `uname -r` in a macOS Tart VM cloned from `ghcr.io/cirruslabs/macos-sonoma-base:latest`.
+
+See plugin's [Configuration section](https://github.com/cirruslabs/tart-buildkite-plugin#configuration) for the full list of available options.

mkdocs.yml

@@ -91,6 +91,7 @@ nav:
   - "Integrations":
     - "GitHub Actions": integrations/github-actions.md
     - "GitLab Runner": integrations/gitlab-runner.md
+    - "Buildkite": integrations/buildkite.md
     - "Self-hosted CI": integrations/cirrus-cli.md
     - "Managing VMs": integrations/vm-management.md
   - "Support & Licensing": licensing.md