suggested_users.rb

class SuggestedUsers
  attr_reader :user

  def initialize(user)
    @user = user
  end

  def suggested_users
    User.joins('JOIN follows as follows_follows ON follows_follows.followee_id = users.id')
        .joins('JOIN follows as user_follows ON follows_follows.follower_id = user_follows.followee_id')
        .where('follows_follows.followee_id NOT IN (SELECT followee_id FROM follows WHERE follower_id = :user_id)', user_id: user.id)
        .where('user_follows.follower_id = :user_id', user_id: user.id)
  end
  alias_method :all, :suggested_users
end