Add AWS AppSync to the list of services (graphql#477)

Author: tinnou

site/code/index.html.js

@@ -440,6 +440,7 @@ Executor.execute(schema, query) map println
   - [Reindex](https://www.reindex.io/baas/) ([github](https://github.com/reindexio/reindex-js)): A BaaS (Backend as a Service) that sets you up with a GraphQL backend targeted at applications using React and Relay.
   - [Scaphold](https://scaphold.io) ([github](https://github.com/scaphold-io)): A BaaS (Backend as a Service) that sets you up with a GraphQL backend for your applications with many different integrations.
   - [Tipe](https://tipe.io) ([github](https://github.com/tipeio)): A SaaS (Software as a Service) content management system that allows you to create your content with powerful editing tools and access it from anywhere with a GraphQL or REST API.
+  - [AWS AppSync](https://aws.amazon.com/appsync/): Fully managed GraphQL service with realtime subscriptions, offline programming & synchronization, and enterprise security features as well as fine grained authorization controls.
 
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