Extract counters from accounts table to account_stats table (#9295)

app/models/concerns/account_counters.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module AccountCounters
+  extend ActiveSupport::Concern
+
+  included do
+    has_one :account_stat, inverse_of: :account
+    after_save :save_account_stat
+  end
+
+  delegate :statuses_count,
+           :statuses_count=,
+           :following_count,
+           :following_count=,
+           :followers_count,
+           :followers_count=,
+           :increment_count!,
+           :decrement_count!,
+           to: :account_stat
+
+  def account_stat
+    super || build_account_stat
+  end
+
+  private
+
+  def save_account_stat
+    return unless account_stat&.changed?
+    account_stat.save
+  end
+end