Example making "cohorts" for product analytics

[danthegoodman1]

If we have a set of pre-known cohorts (give us a name and a query) that we can turn into a materialized view then we can inject that where found into future queries.

For example the flow can look like:

1. Some user creates a completed_onboarding cohort
2. We create a materialized view called that
3. They run a query where _completed_onboarding (indicates using a pre-defined table, maybe we do $completed_onboarding so it's clear there will be injection as otherwise that's improper sql) where they check for folks who completed onboarding in different regions.