Remove Danbooru Winter Sale.

app/models/user.rb

@@ -404,9 +404,7 @@ class User < ApplicationRecord
     end
 
     def tag_query_limit
-      if is_member? && Danbooru.config.is_promotion?
-        1_000_000
-      elsif is_platinum?
+      if is_platinum?
         Danbooru.config.base_tag_query_limit * 2
       elsif is_gold?
         Danbooru.config.base_tag_query_limit

app/models/user_upgrade.rb

@@ -35,11 +35,7 @@ class UserUpgrade < ApplicationRecord
   end
 
   def self.gold_price
-    if Danbooru.config.is_promotion?
-      1500
-    else
-      2000
-    end
+    2000
   end
 
   def self.platinum_price
@@ -168,9 +164,6 @@ class UserUpgrade < ApplicationRecord
           price: price_id,
           quantity: 1,
         }],
-        discounts: [{
-          coupon: promotion_discount_id,
-        }],
         metadata: {
           user_upgrade_id: id,
           purchaser_id: purchaser.id,
@@ -228,12 +221,6 @@ class UserUpgrade < ApplicationRecord
       !pending?
     end
 
-    def promotion_discount_id
-      if Danbooru.config.is_promotion?
-        Danbooru.config.stripe_promotion_discount_id
-      end
-    end
-
     def upgrade_price_id(currency)
       case [upgrade_type, currency]
       when ["gold", "usd"]