add invalid date to errors

referrals_controller.rb

 def create

    @referral = Referral.new(referral_params)

    begin
      params[:referral][:dob] = Date.strptime(params[:referral][:dob], '%m/%d/%Y')
    rescue
      @referral.errors.add(:dob, 'Invalid Date')
    end

    if @referral.save
      redirect_to confirmation_page_referrals_path, notice: "Thank you for submitting this referral to Eminence Healthcare."
    else
      render :new
    end
  end