Add a full example of using yml anchors

_data/docs.yml

@@ -11,6 +11,8 @@
       url: /docs/configuration/accessories/
     - title: "Aliases"
       url: /docs/configuration/aliases/
+    - title: "Anchors"
+      url: /docs/configuration/anchors/
     - title: "Booting"
       url: /docs/configuration/booting/
     - title: "Builders"

docs/configuration/anchors.md

@@ -0,0 +1,30 @@
+---
+title: Anchors
+---
+
+# Anchors
+
+You can re-use parts of your Kamal configuration by defining them as anchors and referencing them with aliases.
+
+For example, you might need to define a shared healthcheck for multiple worker roles. Anchors
+begin with `x-` and are defined at the root level of your deploy.yml file.
+
+```yaml
+x-worker-healthcheck: &worker-healthcheck
+  health-cmd: bin/worker-healthcheck
+  health-start-period: 5s
+  health-retries: 5
+  health-interval: 5s
+```
+
+To use this anchor in your deploy configuration, reference it via the alias.
+
+```yaml
+servers:
+  worker:
+    hosts:
+      - 867.53.0.9
+    cmd: bin/jobs
+    options:
+      <<: *worker-healthcheck
+```