If a user always read all group messages, we will never update the
`first_pm_unread_at` column since the previous query will not return the
group_user. Instead, we should update `first_pm_unread_at` to the
current timestamp if the user has read everything.
Follow-up to 9b75d95fc6
For sites that are configured to mute some or all categories and tags
for users by default, groups can now be configured to set members'
notification level to normal from the group manage UI.
* FEATURE: set notification levels when added to a group
This feature allows admins and group owners to define default
category and tag tracking levels that will be applied to user
preferences automatically at the time when users are added to the
group. Users are free to change those preferences afterwards.
When removed from a group, the user's notification preferences aren't
changed.
This change both speeds up specs (less strings to allocate) and helps catch
cases where methods in Discourse are mutating inputs.
Overall we will be migrating everything to use #frozen_string_literal: true
it will take a while, but this is the first and safest move in this direction
