Fix saved searces, news updates, ip bans being dumped to BigQuery.

Prevent saved searches, news updates, and ip bans from being publicly
dumped to BigQuery. They didn't override the `visible` method to
restrict their visibility for anonymous users.

app/models/news_update.rb

@@ -2,4 +2,18 @@ class NewsUpdate < ApplicationRecord
   belongs_to :creator, class_name: "User"
   belongs_to_updater
   scope :recent, -> {where("created_at >= ?", 2.weeks.ago).order("created_at desc").limit(5)}
+
+  def self.visible(user)
+    if user.is_admin?
+      all
+    else
+      none
+    end
+  end
+
+  def self.search(params)
+    q = search_attributes(params, :id, :created_at, :updated_at, :message, :creator, :updater)
+    q = q.apply_default_order(params)
+    q
+  end
 end