Add documentation to use with apollo-server-lambda

[aryaminus]

The number of audience who have Serverless Subscriptions issue are certain to use apollo-server-lambda. It would be better if you build an example using it or atleast some guide

[gobengo]

I'm not sure if it's possible, tbh.

The goal here is to support subscriptions. apollo-server-lambda's ApolloServer doesn't (I believe) even try to.

The approach that's worked for us is just to use apollo-server-express, then use aws-serverless-epxress to translate lambda requests to be able to call the express server.

This has the benefit of being able to develop the app locally too as a normal http server, or run the same apollo app on non-lambda deployment targets.

What benefit does apollo-server-lambda provide over this method?

[aryaminus]

Well, maybe for someone deploying to netlify using netlify-lambda, or something similar