Add cold-start follow recommendations (#15945)

app/models/follow_recommendation_suppression.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+# == Schema Information
+#
+# Table name: follow_recommendation_suppressions
+#
+#  id         :bigint(8)        not null, primary key
+#  account_id :bigint(8)        not null
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+
+class FollowRecommendationSuppression < ApplicationRecord
+  include Redisable
+
+  belongs_to :account
+
+  after_commit :remove_follow_recommendations, on: :create
+
+  private
+
+  def remove_follow_recommendations
+    redis.pipelined do
+      I18n.available_locales.each do |locale|
+        redis.zrem("follow_recommendations:#{locale}", account_id)
+      end
+    end
+  end
+end