Merge branch '34370-configure-group-push-rules-docs' into 'master'

Add docs about group push rules

See merge request gitlab-org/gitlab!25282

doc/push_rules/push_rules.md

@@ -68,7 +68,7 @@ See [server hooks](../administration/server_hooks.md) for more information.
 NOTE: **Note:**
 GitLab administrators can set push rules globally under
 **Admin Area > Push Rules** that all new projects will inherit. You can later
-override them in a project's settings.
+override them in a project's settings. They can be also set on a [group level](../user/group/index.md#group-push-rules-starter).
 
 1. Navigate to your project's **Settings > Repository** and expand **Push Rules**
 1. Set the rule you want

doc/user/group/index.md

@@ -596,6 +596,29 @@ For performance reasons, we may delay the update up to 1 hour and 30 minutes.
 
 If your namespace shows `N/A` as the total storage usage, you can trigger a recalculation by pushing a commit to any project in that namespace.
 
+#### Group push rules **(STARTER)**
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/issues/34370) in [GitLab Starter](https://about.gitlab.com/pricing/) 12.8.
+
+Group push rules allow group maintainers to set
+[push rules](../../push_rules/push_rules.md) for newly created projects within the specific group.
+
+To configure push rules for a group, navigate to **{push-rules}** on the group's
+sidebar.
+
+When set, new subgroups have push rules set for them based on either:
+
+- The closest parent group with push rules defined.
+- Push rules set at the instance level, if no parent groups have push rules defined.
+
+##### Enabling the feature
+
+This feature comes with the `:group_push_rules` feature flag disabled by default. It can be enabled for specific group using feature flag [API endpoint](../../api/features.md#set-or-create-a-feature) or by GitLab administrator with Rails console access by running:
+
+```ruby
+Feature.enable(:group_push_rules)
+```
+
 ### Maximum artifacts size **(CORE ONLY)**
 
 For information about setting a maximum artifact size for a group, see