Referrals for rails user controller

user_controller.rb

# Add referrals only to new users                                                         
referred_by = params[:referred_by]
if referred_by.present?
  if User.exists?(referred_by)
    referrer = User.find(referred_by)
    subscription = PaymentSystem.get_subscription(referrer.subscription_id)
    if subscription.trial_end > Time.now.to_i
      subscription.trial_end = (Time.at(subscription.trial_end) + 90.days).to_i
    else
      subscription.trial_end = (Time.now + 90.days).to_i
    end
    subscription.save
    @user.referred_by = referred_by.to_i
  end
end