Document usage of GraphQL Pro

doc/development/api_graphql_styleguide.md

@@ -13,6 +13,7 @@ This document outlines the style guide for the GitLab [GraphQL API](../api/graph
 <!-- vale gitlab.Spelling = NO -->
 We use the [GraphQL Ruby gem](https://graphql-ruby.org/) written by [Robert Mosolgo](https://github.com/rmosolgo/).
 <!-- vale gitlab.Spelling = YES -->
+In addition, we have a subscription to [GraphQL Pro](https://www.graphql.pro). For details see [GraphQL Pro subscription](graphql_guide/graphql_pro.md).
 
 All GraphQL queries are directed to a single endpoint
 ([`app/controllers/graphql_controller.rb#execute`](https://gitlab.com/gitlab-org/gitlab/blob/master/app%2Fcontrollers%2Fgraphql_controller.rb)),

doc/development/graphql_guide/graphql_pro.md

+---
+stage: Plan
+group: Project Management
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
+---
+
+# GraphQL Pro
+
+GraphQL has become a key technology in GitLab and is implemented using the 
+[GraphQL Ruby gem](https://graphql-ruby.org). As such, we've purchased a subscription to
+[GraphQL Pro](https://graphql.pro).
+
+The main purpose is for support. Per the website:
+
+> As a GraphQL::Pro customer, you get direct access to the GraphQL Ruby gem
+> creator and maintainer. Get prioritized support for issues and requests.
+
+Note that we **cannot** use the Pro version directly in our product, since we are 
+an Open Core product - we can not require customers to purchase the Pro version, nor can we ship it.
+
+Details on the billing account and gem licensing can be found in the Engineering 1Password vault.

doc/development/graphql_guide/index.md

 ---
-stage: none
-group: unassigned
+stage: Plan
+group: Project Management
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---
 
@@ -17,3 +17,6 @@ feedback, and suggestions.
 - [GraphQL API documentation style guide](../documentation/graphql_styleguide.md): documentation
   style guide for GraphQL.
 - [GraphQL API](../../api/graphql/index.md): user documentation for the GitLab GraphQL API.
+- [GraphQL BatchLoader](batchloader.md): development documentation on the batchloader.
+- [GraphQL pagination](pagination.md): development documentation on pagination.
+- [GraphQL Pro](graphql_pro.md): information on our GraphQL Pro subscription.

doc/development/graphql_guide/pagination.md

 ---
-stage: none
-group: unassigned
+stage: Plan
+group: Project Management
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 ---