offline-first

Library Affected:
workbox-strategies

We currently have code for a "cache and network race" strategy in our docs. The entirety of it looks like:

import {Strategy} from 'workbox-strategies';

class CacheNetworkRace extends Strategy {
  _handle(request, handler) {
 

In Settings : 'Add a new side account' button

Step #2 in Side account creation

(a very light & quick version of onboarding, with only nickname step)
![side account mode copy](https://user-images.githubusercontent.com/37345040/99953009-dd7db900-2d80-11eb-9f6f-e

Here is an issues with detailed description: NekR/offline-plugin#77

I think this is missing handling for indexes that are in basisIndexes but missing from this.indexes.

Originally posted by @grgbkr in rocicorp/replicache#974 (comment)