Fix #4148: Don't prune votes.

app/models/post_vote.rb

@@ -11,10 +11,6 @@ class PostVote < ApplicationRecord
   after_create :update_post_on_create
   after_destroy :update_post_on_destroy
 
-  def self.prune!
-    where("created_at < ?", 90.days.ago).delete_all
-  end
-
   def self.positive_user_ids
     select_values_sql("select user_id from post_votes where score > 0 group by user_id having count(*) > 100")
   end