Rails associations and create method question... How do I create a new lead for user_id: 1 --and at the same time create the referral association?

home_controller.rb

....


  def create
      @lead = Lead.new(email: params[:user][:email], user_id: 1)

      respond_to do |format|
        if @lead.save
          format.html { redirect_to @lead, notice: 'User was successfully created.' }
          format.json { render json: @lead, status: :created, location: @lead }
        else
          format.html { render "new" }
          format.json { render json: @lead.errors, status: :unprocessable_entity }
        end
      end
    end
    
  ...

Lead.rb

class Lead < ActiveRecord::Base
  attr_accessible :email
  has_one :referral
  has_one :user, :through => :referrals
end

Referral.rb

class Referral < ActiveRecord::Base
  attr_accessible :lead_id, :user_id
  belongs_to :user
  belongs_to :lead
end

User.rb

class User < ActiveRecord::Base
  has_secure_password
  has_many :referrals
  has_many :leads, :through => :referrals
  attr_accessible :address, :city, :email, :first_name, :last_name, :phone, :state, :zip, :password, :password_confirmation, :slug, :referred_by
  validates_uniqueness_of :email
  validates_presence_of :email
  validates_presence_of :password
  def name
    [first_name, last_name].join " "
  end
end