Previous behaviour was to silently remove tags that
belonged to a group with a parent tag that was missing.
The "required parent tag" feature is meant to guide people
to use the correct tags and show scoped results in the tag
input field, and to help create topic lists of related
tags. It isn't meant to be a strict requirement in the
composer that should trigger errors or restrictions.
A new checkbox has been added to the Tags tab of the category settings modal
which is used when some tags and/or tag groups are restricted to the category,
and all other unrestricted tags should also be allowed.
Default is the same as the previous behaviour: only allow the specified set of
tags and tag groups in the category.
- By default, behaviour is not changed: tags are made lowercase upon creation and edit.
- If force_lowercase_tags is disabled, then mixed case tags are allowed.
- Tags must remain case-insensitively unique. This is enforced by ActiveRecord and Postgres.
- A migration is added to provide a `UNIQUE` index on `lower(name)`. Migration includes a safety to correct any current tags that do not meet the criteria.
- A `where_name` scope is added to `models/tag.rb`, to allow easy case-insensitive lookups. This is used instead of `Tag.where(name: "blah")`.
- URLs remain lowercase. Mixed case URLs are functional, but have the lowercase equivalent as the canonical.
- present tags watched on the user prefs page
- automatically watch or unwatch old topics based on watch status
New watching and tracking logic takes care of handling old topics
(either with or without read state)
When you watch a topic you now watch historically
Also removes confusing warnings from user.