user.update_attributes(name: "Example User" , email:"example@railstutorial.org" , password:"foobar" , password_confirmation:"foobar")

NameError: undefined local variable or method `user' for main:Object

class UsersController < ApplicationController

  def show
    @user = User.find_by(params[:id])
  end

  def new
  end
end

class User < ApplicationRecord
  before_save { email.downcase! }
  validates :name,  presence: true, length: { maximum: 50 }
  VALID_EMAIL_REGEX = /A[w+-.]+@[a-zd-]+(.[a-zd-]+)*.[a-z]+z/i
  validates :email, presence: true, length: { maximum: 255 },
                    format: { with: VALID_EMAIL_REGEX },
                    uniqueness: { case_sensitive: false }
  has_secure_password
  validates :password, presence: true, length: { minimum: 6 }
end