1class CreateUsers < ActiveRecord::Migration
 2  def change
 3    create_table :users, id: :uuid, default: 'uuid_generate_v4()' do |t|
 4      t.string :username, null: false
 5      t.string :password_digest, null: false
 6
 7      t.timestamps null: false
 8    end
 9
10    add_index :users, :username, unique: true
11  end
12end