Highlight the switch to apollo-client
Highlight the switch to apollo-client

Users who have followed the getting started guide are likely still using Apollo Boost which doesn't support adding custom links. Switching to the proper ApolloClient is necessary to get the header authorization working (and cookie auth only works because the Apollo Boost defaults include `credentials: 'same-origin'` already.
apollographql/apollo-client,apollostack/apollo-client,apollographql/apollo-client,apollostack/apollo-client,apollostack/apollo-client