Merge pull request #3393 from evazion/feat-safe-mode

Fix #3392: Add safe mode account setting.

config/danbooru_default_config.rb

@@ -151,6 +151,11 @@ module Danbooru
       2
     end
 
+    # Whether safe mode should be enabled. Safe mode hides all non-rating:safe posts from view.
+    def enable_safe_mode?(request, user)
+      !!(request.host =~ /safe/ || request.params[:safe_mode] || user.enable_safe_mode?)
+    end
+
     # Determines who can see ads.
     def can_see_ads?(user)
       !user.is_gold?