Record enough information on a campaign to return all involved users in a campaign
Created by: mrnugget
This is the backend work necessary to implement the API proposed in https://github.com/sourcegraph/sourcegraph/issues/12465.
We need to:
- record a timestamp when a campaign spec has been applied (why? when the campaign is new, it's
campaign.created_at, but when the campaign is updated, we need a separate timestamp) - rename the
campaigns.author_idfield tocampaigns.initial_applier_idand set it when the campaign is created. - add a
campaigns.applier_idfield and populate it whenever a campaign spec is applied with the current user that does the application - change the campaign/campaign spec resolvers depending on the API in #12465 (closed)