Move customization subheadings to new page

Create a new child page, Customizing Auto DevOps, from a large
portion of the parent page.

doc/ci/variables/README.md

@@ -453,7 +453,7 @@ pass CI variables to the running application by prefixing the key of the
 variable with `K8S_SECRET_`.
 
 These [prefixed
-variables](../../topics/autodevops/index.md#application-secret-variables) will
+variables](../../topics/autodevops/customize.md#application-secret-variables) will
 then be available as environment variables on the running application
 container.
 

doc/development/integrations/secure.md

@@ -80,7 +80,7 @@ See [GitLab CI/CD predefined variables](../../ci/variables/predefined_variables.
 
 Also, scanning jobs should be skipped when the corresponding variable prefixed with `_DISABLED` is present.
 See `DEPENDENCY_SCANNING_DISABLED`, `CONTAINER_SCANNING_DISABLED`, `SAST_DISABLED`, and `DAST_DISABLED`
-in [Auto DevOps documentation](../../topics/autodevops/index.md#disable-jobs).
+in [Auto DevOps documentation](../../topics/autodevops/customize.md#disable-jobs).
 
 Finally, SAST and Dependency Scanning job definitions should use
 `CI_PROJECT_REPOSITORY_LANGUAGES` (comma-separated list of values)

doc/topics/application_development_platform/index.md

@@ -37,7 +37,7 @@ with various cloud providers.
 In order to provide modern DevOps workflows, our Application Development Platform will rely on
 [Auto DevOps](../autodevops/index.md) to provide those workflows. Auto DevOps works with
 any Kubernetes cluster; you're not limited to running on GitLab's infrastructure. Additionally, Auto DevOps offers
-an incremental consumption path. Because it is [composable](../autodevops/index.md#using-components-of-auto-devops),
+an incremental consumption path. Because it is [composable](../autodevops/customize.md#using-components-of-auto-devops),
 you can use as much or as little of the default pipeline as you'd like, and deeply customize without having to integrate a completely different platform.
 
 ### Security

doc/topics/autodevops/quick_start_guide.md

@@ -207,7 +207,7 @@ deployment and clicking a square will take you to the pod's logs page.
 
 TIP: **Tip:**
 There is only one pod hosting the application at the moment, but you can add
-more pods by defining the [`REPLICAS` variable](index.md#environment-variables)
+more pods by defining the [`REPLICAS` variable](customize.md#environment-variables)
 under **Settings > CI/CD > Environment variables**.
 
 ### Working with branches
@@ -278,8 +278,8 @@ and customized to fit your workflow. Here are some helpful resources for further
 
 1. [Auto DevOps](index.md)
 1. [Multiple Kubernetes clusters](index.md#using-multiple-kubernetes-clusters-premium) **(PREMIUM)**
-1. [Incremental rollout to production](index.md#incremental-rollout-to-production-premium) **(PREMIUM)**
-1. [Disable jobs you don't need with environment variables](index.md#environment-variables)
+1. [Incremental rollout to production](customize.md#incremental-rollout-to-production-premium) **(PREMIUM)**
+1. [Disable jobs you don't need with environment variables](customize.md#environment-variables)
 1. [Use a static IP for your cluster](../../user/clusters/applications.md#using-a-static-ip)
-1. [Use your own buildpacks to build your application](index.md#custom-buildpacks)
+1. [Use your own buildpacks to build your application](customize.md#custom-buildpacks)
 1. [Prometheus monitoring](../../user/project/integrations/prometheus.md)

doc/topics/autodevops/stages.md

@@ -19,7 +19,7 @@ If a project's repository contains a `Dockerfile` at its root, Auto Build will u
 If you are also using Auto Review Apps and Auto Deploy and choose to provide
 your own `Dockerfile`, make sure you expose your application to port
 `5000` as this is the port assumed by the
-[default Helm chart](https://gitlab.com/gitlab-org/charts/auto-deploy-app). Alternatively you can override the default values by [customizing the Auto Deploy Helm chart](index.md#custom-helm-chart)
+[default Helm chart](https://gitlab.com/gitlab-org/charts/auto-deploy-app). Alternatively you can override the default values by [customizing the Auto Deploy Helm chart](customize.md#custom-helm-chart)
 
 ### Auto Build using Heroku buildpacks
 
@@ -78,7 +78,7 @@ Auto Test automatically runs the appropriate tests for your application using
 buildpacks](https://devcenter.heroku.com/articles/buildpacks) by analyzing
 your project to detect the language and framework. Several languages and
 frameworks are detected automatically, but if your language is not detected,
-you may succeed with a [custom buildpack](index.md#custom-buildpacks). Check the
+you may succeed with a [custom buildpack](customize.md#custom-buildpacks). Check the
 [currently supported languages](index.md#currently-supported-languages).
 
 Auto Test uses tests you already have in your application. If there are no
@@ -182,7 +182,7 @@ be deleted.
 
 Review apps are deployed using the
 [auto-deploy-app](https://gitlab.com/gitlab-org/charts/auto-deploy-app) chart with
-Helm, which can be [customized](index.md#custom-helm-chart). The app will be deployed into the [Kubernetes
+Helm, which can be [customized](customize.md#custom-helm-chart). The app will be deployed into the [Kubernetes
 namespace](../../user/project/clusters/index.md#deployment-variables)
 for the environment.
 
@@ -265,8 +265,8 @@ Auto Deploy doesn't include deployments to staging or canary by default, but the
 [Auto DevOps template](https://gitlab.com/gitlab-org/gitlab/blob/master/lib/gitlab/ci/templates/Auto-DevOps.gitlab-ci.yml) contains job definitions for these tasks if you want to
 enable them.
 
-You can make use of [environment variables](index.md#environment-variables) to automatically
-scale your pod replicas and to apply custom arguments to the Auto DevOps `helm upgrade` commands. This is an easy way to [customize the Auto Deploy Helm chart](index.md#custom-helm-chart).
+You can make use of [environment variables](customize.md#environment-variables) to automatically
+scale your pod replicas and to apply custom arguments to the Auto DevOps `helm upgrade` commands. This is an easy way to [customize the Auto Deploy Helm chart](customize.md#custom-helm-chart).
 
 Apps are deployed using the
 [auto-deploy-app](https://gitlab.com/gitlab-org/charts/auto-deploy-app) chart with
@@ -315,7 +315,7 @@ including support for `Deployment` in the `extensions/v1beta1` version.
 
 To use Auto Deploy on a Kubernetes 1.16+ cluster, you must:
 
-1. Set the following in the [`.gitlab/auto-deploy-values.yaml` file](index.md#customize-values-for-helm-chart):
+1. Set the following in the [`.gitlab/auto-deploy-values.yaml` file](customize.md#customize-values-for-helm-chart):
 
    ```yml
    deploymentApiVersion: apps/v1
@@ -391,7 +391,7 @@ need to:
 
 Once you have configured your worker to respond to health checks, run a Sidekiq
 worker for your Rails application. You can enable workers by setting the
-following in the [`.gitlab/auto-deploy-values.yaml` file](index.md#customize-values-for-helm-chart):
+following in the [`.gitlab/auto-deploy-values.yaml` file](customize.md#customize-values-for-helm-chart):
 
 ```yml
 workers:

doc/topics/autodevops/upgrading_postgresql.md

 # Upgrading PostgreSQL for Auto DevOps
 
-Auto DevOps provides an [in-cluster PostgreSQL database](index.md#postgresql-database-support)
+Auto DevOps provides an [in-cluster PostgreSQL database](customize.md#postgresql-database-support)
 for your application.
 
 The version of the chart used to provision PostgreSQL:

doc/user/application_security/security_dashboard/index.md

@@ -156,7 +156,7 @@ That way, reports are created even if no code change happens.
 ## Security scans using Auto DevOps
 
 When using [Auto DevOps](../../../topics/autodevops/index.md), use
-[special environment variables](../../../topics/autodevops/index.md#environment-variables)
+[special environment variables](../../../topics/autodevops/customize.md#environment-variables)
 to configure daily security scans.
 
 <!-- ## Troubleshooting

doc/user/project/clusters/add_eks_clusters.md

@@ -279,7 +279,7 @@ If a default Storage Class doesn't already exist and is desired, follow Amazon's
 to create one.
 
 Alternatively, disable PostgreSQL by setting the project variable
-[`POSTGRES_ENABLED`](../../../topics/autodevops/#environment-variables) to `false`.
+[`POSTGRES_ENABLED`](../../../topics/autodevops/customize.md#environment-variables) to `false`.
 
 ### Deploy the app to EKS