Surface batch change reviewer in dashboard

Created by: malomarrec

Problem to solve

A lot of customers don't use codehost notifications. To get changesets merged, the batch changes owner need to identify the changeset reviewers to follow up with.

Solution summary

Assuming customers have a way to auto-assign reviewers to changesets (eg. with CODEOWNERS), we could make following up with customers easier by showing the reviewer directly in the dashboard. That'd allow customers to:

• quickly view who owns reviewing a changeset
• pull the list of reviewers with changesets that need review

Impacted customers

• https://github.com/sourcegraph/accounts/issues/244 (product gap: https://sourcegraph2020.lightning.force.com/lightning/r/Product_Gap_Submission__c/a1C5b00000AFN5pEAH/view)

Delivery plan

• evaluate if codehosts API support getting reviewers
• get additional feedback on this solution