improve achievement management and and views

db/migrate/20210815182601_add_wow_achievement_category_self_join.rb

@@ -0,0 +1,5 @@
+class AddWowAchievementCategorySelfJoin < ActiveRecord::Migration[6.1]
+  def change
+    add_reference :wow_achievement_categories, :parent_category, foreign_key: { to_table: :wow_achievement_categories }
+  end
+end

db/migrate/20210815182820_add_columns_to_wow_achievement_category.rb

@@ -0,0 +1,6 @@
+class AddColumnsToWowAchievementCategory < ActiveRecord::Migration[6.1]
+  def change
+    add_column :wow_achievement_categories, :is_guild_category, :boolean
+    add_column :wow_achievement_categories, :display_order, :integer
+  end
+end