jobs: drop favgroup expunge job.

Make `Post#expunge!` remove favgroups synchronously.

app/models/favorite_group.rb

@@ -178,13 +178,6 @@ class FavoriteGroup < ApplicationRecord
     end
   end
 
-  def self.purge_post(post_id)
-    post_id = post_id.id if post_id.is_a?(Post)
-    for_post(post_id).find_each do |group|
-      group.remove!(post_id)
-    end
-  end
-
   def remove!(post_id)
     with_lock do
       post_id = post_id.id if post_id.is_a?(Post)

app/models/post.rb

@@ -1000,7 +1000,9 @@ class Post < ApplicationRecord
     end
 
     def remove_from_fav_groups
-      FavoriteGroup.delay.purge_post(id)
+      FavoriteGroup.for_post(id).find_each do |favgroup|
+        favgroup.remove!(id)
+      end
     end
   end
 

test/unit/post_test.rb

@@ -41,6 +41,7 @@ class PostTest < ActiveSupport::TestCase
         @upload = UploadService.new(FactoryBot.attributes_for(:jpg_upload)).start!
         @post = @upload.post
         Favorite.add(post: @post, user: @user)
+        create(:favorite_group).add!(@post.id)
       end
 
       teardown do
@@ -63,6 +64,12 @@ class PostTest < ActiveSupport::TestCase
         assert_equal(0, Favorite.for_user(@user.id).where("post_id = ?", @post.id).count)
       end
 
+      should "remove all favgroups" do
+        assert_equal(1, FavoriteGroup.for_post(@post.id).count)
+        @post.expunge!
+        assert_equal(0, FavoriteGroup.for_post(@post.id).count)
+      end
+
       should "decrement the uploader's upload count" do
         assert_difference("@post.uploader.reload.post_upload_count", -1) do
           @post.expunge!