Profiling showed that we were roughly 10% of a request time creating all
the ActiveRecord objects for categories in the `Site` model on a site with 61 categories.
Instead of querying for the categories each time based on which categories the user can see,
we can just preload all of the categories upfront and filter out the
categories that the user can not see.
Now that we have support for user-selectable color schemes, it makes sense
to simplify seeding and theme updates in the wizard.
We now:
- seed only one theme, named "Default" (previously "Light")
- seed a user-selectable Dark color scheme
- rename the "Themes" wizard step to "Colors"
- update the default theme's color scheme if a default is set
(a new theme is created if there is no default)
Like "default watching" and "default tracking" categories option now the "regular" categories support is added. It will be useful for sites that are muted by default. The user option will be displayed only if `mute_all_categories_by_default` site setting is enabled.
Zeitwerk simplifies working with dependencies in dev and makes it easier reloading class chains.
We no longer need to use Rails "require_dependency" anywhere and instead can just use standard
Ruby patterns to require files.
This is a far reaching change and we expect some followups here.
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
