message: Explain clearly that modules are isolated
diff: @@ -7,7 +7,7 @@ sidebar_label: Context
  In GraphQL, a context is an object shared by all the resolvers of a specific execution.
  It's useful for keeping data such as authentication info, the current user, database connection, data sources and other things you need for running your business logic.
  -The context is available as the 3rd argument of each resolver:
  +The context is available as the 3rd argument to each resolver:
  ```typescript
  const resolvers = {
  @@ -19,6 +19,8 @@ const resolvers = {
  > You can read more about resolver in **[Apollo Server documentation](https://www.apollographql.com/docs/graphql-tools/resolvers#Resolver-function-signature)**.
  +Since modules are isolated (see [why](https://medium.com/the-guild/why-is-true-modular-encapsulation-so-important-in-large-scale-graphql-projects-ed1778b03600)), there is no common context unless you explicitly create one. In the [case of authentication](https://www.apollographql.com/docs/apollo-server/security/authentication/#putting-user-info-on-the-context) for example, you need to create an authentication module that places the authenticated user into the context, then explicitly import that authentication module from each module that uses authentication.
  +
  GraphQL Modules also uses the context; it adds to the context a field called `injector`, which you can use to get access to the dependency injection container of your `GraphQLModule`.
  You can use the `injector` from any resolver like that:
  