Move Curated pool updater to Danbooru.

* Move the Curated pool updater from Reportbooru to Danbooru.

* Change the process for selecting curated posts. Previously it was
  every post from the last week with at least three supervotes. This was
  flawed because it included both super-upvotes and super-downvotes. Now
  it's the top 100 posts from the last week, ordered from most super-upvoted
  to least.

app/logical/curated_pool_updater.rb

@@ -0,0 +1,16 @@
+module CuratedPoolUpdater
+  def self.curated_posts(date_range: (1.week.ago..Time.now), limit: 100)
+    posts = Post.where(created_at: date_range)
+    posts = posts.joins(:votes).where("post_votes.score": SuperVoter::MAGNITUDE)
+    posts = Post.where(id: posts.group(:id).order(Arel.sql("COUNT(*) DESC")).limit(limit))
+    posts
+  end
+
+  def self.update_pool!(pool_id = Danbooru.config.curated_pool_id)
+    return unless pool_id.present?
+
+    CurrentUser.scoped(User.system, "127.0.0.1") do
+      Pool.find(pool_id).update!(post_ids: curated_posts.pluck(:id))
+    end
+  end
+end

app/logical/danbooru_maintenance.rb

@@ -21,6 +21,7 @@ module DanbooruMaintenance
     TagChangeRequestPruner.warn_all
     TagChangeRequestPruner.reject_all
     Ban.prune!
+    CuratedPoolUpdater.update_pool!
 
     ActiveRecord::Base.connection.execute("vacuum analyze") unless Rails.env.test?
   rescue Exception => exception

config/danbooru_default_config.rb

@@ -41,6 +41,11 @@ module Danbooru
       ForumTopic.where(title: "Upload Feedback Thread").first
     end
 
+    # The ID of the "Curated" pool. If present, this pool will be updated daily with curated posts.
+    def curated_pool_id
+      nil
+    end
+
     def source_code_url
       "https://github.com/r888888888/danbooru"
     end

test/unit/danbooru_maintenance_test.rb

@@ -3,13 +3,20 @@ require 'test_helper'
 class DanbooruMaintenanceTest < ActiveSupport::TestCase
   context "daily maintenance" do
     setup do
-      FactoryBot.create(:admin_user) # for SuperVoter.init!
+      @admin = create(:admin_user) # for SuperVoter.init!
     end
 
     should "work" do
       assert_nothing_raised { DanbooruMaintenance.daily }
     end
 
+    should "update the curated pool" do
+      pool = as(@admin) { create(:pool, name: "curated") }
+      Danbooru.config.stubs(:curated_pool_id).returns(pool.id)
+
+      assert_nothing_raised { DanbooruMaintenance.daily }
+    end
+
     should "prune expired posts" do
       @pending = FactoryBot.create(:post, is_pending: true, created_at: 4.days.ago)
       @flagged = FactoryBot.create(:post, is_flagged: true, created_at: 4.days.ago)