Docs: add custom commands page; alphabetical order of howto

docs/howto/custom-commands.mdx

@@ -0,0 +1,28 @@
+---
+title: "Custom commands"
+---
+
+You can specify custom steps using the `workflows` section in digger.yml. Handy for integration with other CLIs like infracost.
+
+```
+projects:
+- name: production
+  dir: prod
+  workflow: with-infracost
+
+workflows:
+  with-infracost:
+    plan:
+      steps:
+        - init
+        - plan
+        - run: infracost breakdown --path=. | tee -a $DIGGER_OUT
+```
+
+# $DIGGER_OUT
+
+If your custom command writes into a file path defined in the `$DIGGER_OUT` env variable, then its content will be appended to the comment as "additional output":
+
+![](/images/custom-command-output-infracost.png)
+
+The value of `$DIGER_OUT` defaults to `$RUNNER_TEMP/digger-out.log`; you can change that if needed by setting the env var explicitly.

docs/howto/using-infracost.mdx

@@ -1,13 +1,11 @@
 ---
 title: "Using Infracost"
-description: "This feature is in early development. If you find something that can be improved, please let us know by [filing an issue](https://github.com/diggerhq/digger/issues)"
 ---
 
-<Note>You can configure Digger to use Infracost to estimate cloud costs.</Note>
-
 ## Pre-requisites
 
-Infracost binary needs to be installed into your CI pipeline (see [Infracost docs](https://www.infracost.io/docs/integrations/generic%5Fcicd/))
+- Infracost binary installed into your CI pipeline (see [Infracost docs](https://www.infracost.io/docs/integrations/generic%5Fcicd/))
+- Infracost API key
 
 ## Set up Infracost
 
@@ -26,21 +24,21 @@ Use the official setup-infracost action in your workflow file ([README](https://
 
 ```
 projects:
-  - name: project_a_d
-    dir: ./project_a/development
-    workflow: project_a
+- name: production
+  dir: prod
+  workflow: with-infracost
 
 workflows:
-  project_a:
+  with-infracost:
     plan:
       steps:
         - init
         - plan
-        - run: infracost breakdown --path=.
+        - run: infracost breakdown --path=. | tee -a $DIGGER_OUT
 ```
 
 ## See cost estimate output
 
-After the pipeline run finishes, you should see Infracost breakdown output in your CI job logs:
+After the pipeline run finishes, you should see Infracost breakdown output appended to digger run report comment as additional output:
 
-![](/images/configuration/infracost-example.png)
+![](/images/custom-command-output-infracost.png)

docs/mint.json

@@ -62,24 +62,25 @@
         {
           "group": "How To",
           "pages": [
-              "howto/terragrunt",
-              "howto/using-checkov",
-              "howto/using-infracost",
-              "howto/using-opa-conftest",
-              "howto/multiacc-aws",
-              "howto/project-level-roles",
+              "howto/apply-on-merge",
+              "howto/auto-merge",
+              "howto/backendless-mode",
+              "howto/commenting-strategies",
+              "howto/custom-commands",
+              "howto/destroy-manual",
+              "howto/disable-auto-checkout",
               "howto/generate-projects",
               "howto/include-exclude-patterns",
-              "howto/destroy-manual",
-              "howto/trigger-directly",
+              "howto/multiacc-aws",
               "howto/policy-overrides",
-              "howto/versioning",
-              "howto/disable-auto-checkout",
-              "howto/backendless-mode",
+              "howto/project-level-roles",
               "howto/segregate-cloud-accounts",
-              "howto/apply-on-merge",
-              "howto/auto-merge",
-              "howto/commenting-strategies"
+              "howto/trigger-directly",
+              "howto/using-checkov",
+              "howto/using-infracost",
+              "howto/using-opa-conftest",
+              "howto/using-terragrunt",
+              "howto/versioning"
           ]
         },
         {