Cannot find module './in-memory-data-service' in tour of heroes for Angular2

ng generate service InMemoryData --module=app

Will create the src/app/in-memory-data.service.ts file. Then add the code listed in the tutorial and it will work. AFAIK they don't even imply that in the tutorial so don't feel bad. In fact what they say is

The forRoot() configuration method takes an InMemoryDataService class that primes the in-memory database.

The Tour of Heroes sample creates such a class src/app/in-memory-data.service.ts

Which is gibberish and wrong.

My projects created using current CLI Tools, and I installed this:

npm install angular-in-memory-web-api --save

It works for me.