Add documentation for build minutes quota

doc/user/admin_area/settings/continuous_integration.md

@@ -6,7 +6,7 @@ The maximum size of the [build artifacts][art-yml] can be set in the Admin area
 of your GitLab instance. The value is in MB and the default is 100MB. Note that
 this setting is set for each build.
 
-1. Go to **Admin area > Settings** (`/admin/application_settings`).
+1. Go to the **Admin area ➔ Settings** (`/admin/application_settings`).
 
     ![Admin area settings button](img/admin_area_settings_button.png)
 
@@ -16,5 +16,59 @@ this setting is set for each build.
 
 1. Hit **Save** for the changes to take effect.
 
+## Shared Runners build minutes quota
+
+> [Introduced][ee-1078] in GitLab Enterprise Edition 8.16.
+
+If you have enabled shared Runners for your GitLab instance, you can limit their
+usage by setting a maximum number of build minutes that a group can use on
+shared Runners per month. Set 0 to grant unlimited build minutes.
+While build limits are stored as minutes, the counting is done in seconds.
+
+1. Go to the **Admin area ➔ Settings** (`/admin/application_settings`).
+
+    ![Admin area settings button](img/admin_area_settings_button.png)
+
+1. Navigate to the **Continuous Integration** block and enable the Shared
+   Runners setting. Then set the build minutes quota limit.
+
+    ![Shared Runners build minutes quota](img/ci_shared_runners_build_minutes_quota.png)
+
+1. Hit **Save** for the changes to take effect.
+
+---
+
+While the setting in the Admin area has a global effect, as an admin you can
+also change each group's build minutes quota to override the global value.
+
+1. Navigate to the **Groups** admin area and hit the **Edit** button for the
+   group you wish to change the build minutes quota.
+
+    ![Groups in the admin area](img/admin_area_groups.png)
+
+1. Set the build minutes quota to the desired value and hit **Save changes** for
+   the changes to take effect.
+
+    ![Edit group in the admin area](img/admin_area_group_edit.png)
+
+Once saved, you can see the build quota in the group admin view.
+
+![Group admin info](img/group_quota_view.png)
+
+The quota can also be viewed in the project admin view if shared Runners
+are enabled.
+
+![Project admin info](img/admin_project_quota_view.png)
+
+When the build minutes quota for a group is set to a value different than 0,
+the **Pipelines quota** page is available to the group page settings list.
+
+![Group settings](img/group_settings.png)
+
+You can see there an overview of the build minutes quota of all projects of
+the group.
+
+![Group pipelines quota](img/group_pipelines_quota.png)
 
 [art-yml]: ../../../administration/build_artifacts.md
+[ee-1078]: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1078