Fix #5077: Images rated "Adult" on Newgrounds no longer upload.

app/logical/source/extractor/newgrounds.rb

@@ -30,7 +30,7 @@ module Source
       def page
         return nil if page_url.blank?
 
-        response = http.cache(1.minute).get(page_url)
+        response = http.cookies(vmkIdu5l8m: Danbooru.config.newgrounds_session_cookie).cache(1.minute).get(page_url)
         return nil if response.status == 404
 
         response.parse

config/danbooru_default_config.rb

@@ -271,6 +271,12 @@ module Danbooru
       nil
     end
 
+    # Your Newgrounds "vmkIdu5l8m" cookie. Login to Newgrounds then use the
+    # devtools to find the "vmkIdu5l8m" cookie.
+    def newgrounds_session_cookie
+      nil
+    end
+
     # Your NicoSeiga "user_session" cookie. Login to NicoSeiga then use the
     # devtools to find the "user_session" cookie.
     def nico_seiga_user_session