Merge pull request #1495 from Niennienzz/improve-apq-doc

Update apq.md

docs/content/reference/apq.md

@@ -16,8 +16,8 @@ to register query hash with original query on a server.
 In order to enable Automatic Persisted Queries you need to change your client. For more information see
 [Automatic Persisted Queries Link](https://github.com/apollographql/apollo-link-persisted-queries) documentation.
 
-For the server you need to implement `PersistedQueryCache` interface and pass instance to
-`handler.EnablePersistedQueryCache` option.
+For the server you need to implement the `graphql.Cache` interface and pass an instance to
+the `extension.AutomaticPersistedQuery` type. Make sure the extension is applied to your GraphQL handler.
 
 See example using [go-redis](https://github.com/go-redis/redis) package below:
 ```go