flags: allow approvers to bypass the "can't flag more than once in 3 days" rule.

Allow approvers to bypass the rule that you can't flag a post again if
it was flagged less than 3 days ago. This rule was intended to prevent
flag warring among regular users, which hopefully shouldn't be a problem
among approvers. It was also useless because approvers could always
just directly delete the post even if they couldn't flag it.

Allowing approvers to reflag posts allows them to reinstate flags that
were accidentally approved.

app/models/post_flag.rb

@@ -109,7 +109,7 @@ class PostFlag < ApplicationRecord
     errors.add(:post, "is deleted and cannot be flagged") if post.is_deleted? && !is_deletion
 
     flag = post.flags.in_cooldown.last
-    if !is_deletion && flag.present?
+    if !is_deletion && !creator.is_approver? && flag.present?
       errors.add(:post, "cannot be flagged more than once every #{Danbooru.config.moderation_period.inspect} (last flagged: #{flag.created_at.to_formatted_s(:long)})")
     end
   end

test/unit/post_flag_test.rb

@@ -98,6 +98,21 @@ class PostFlagTest < ActiveSupport::TestCase
           assert(@flag3.errors.empty?)
         end
       end
+
+      should "be able to flag a post in the cooldown period if they're a mod" do
+        @post = create(:post)
+        @flag1 = create(:post_flag, post: @post)
+
+        create(:post_approval, post: @post)
+        assert_equal(false, @post.reload.is_pending?)
+
+        travel_to(Danbooru.config.moderation_period.from_now - 1.minute) do
+          @flag2 = create(:post_flag, post: @post, reason: "something", creator: create(:approver))
+
+          assert_equal(true, @flag2.valid?)
+          assert_equal(true, @post.reload.is_flagged?)
+        end
+      end
     end
   end
 end