Challenge 1: A User Model — Solution

Command:
$ rails generate migration CreateUsers email:string password_digest:string

Migration file:
# db/migrate/20260104000000_create_users.rb
class CreateUsers < ActiveRecord::Migration[7.1]
  def change
    create_table :users do |t|
      t.string :email
      t.string :password_digest
      t.timestamps
    end
  end
end

Model:
# app/models/user.rb
class User < ApplicationRecord
  has_secure_password
  validates :email, presence: true, uniqueness: true
end

=begin
Notes:
- password_digest is a plain string column -- has_secure_password is what
  gives it special meaning (bcrypt hashing, the virtual password/
  password_confirmation attributes), not the column name or type alone.
  Without has_secure_password on the model, password_digest would just be
  an ordinary, unused string column.
- validates :email, uniqueness: true prevents two users from registering
  with the same email address -- has_secure_password itself only handles
  password hashing/authentication, it has no opinion about email
  uniqueness at all.
- t.timestamps adds created_at/updated_at automatically, following the
  same convention as every migration in Course 1.
=end