01_enable_uuid.rb

class EnableUuid < ActiveRecord::Migration
  def change
    enable_extension 'uuid-ossp'
  end
end

02_create_users.rb

class CreateUsers < ActiveRecord::Migration
  def change
    create_table :users, id: :uuid do |t|
      t.string :name
      t.string :email, :null => false
      t.string :encrypted_password, :null => false
      t.string :salt, :null => false
      t.string :reset_password_token, :default => nil
      t.datetime :reset_password_token_expires_at, :default => nil
      t.datetime :reset_password_email_sent_at, :default => nil
      t.integer :failed_logins_count, :default => 0
      t.datetime :lock_expires_at, :default => nil
      t.string :unlock_token, :default => nil
      t.timestamps
    end

    add_index :users, :email, unique: true
    add_index :users, :reset_password_token
  end
end

schema.rb

ActiveRecord::Schema.define(version: 02) do

  # These are extensions that must be enabled in order to support this database
  enable_extension "plpgsql"
  enable_extension "uuid-ossp"
  create_table "users", id: :uuid, default: "uuid_generate_v4()", force: true do |t|
    t.string   "name"
    t.string   "email",                                       null: false
    t.string   "crypted_password",                            null: false
    t.string   "salt",                                        null: false
    t.string   "reset_password_token"
    t.datetime "reset_password_token_expires_at"
    t.datetime "reset_password_email_sent_at"
    t.integer  "failed_logins_count",             default: 0
    t.datetime "lock_expires_at"
    t.string   "unlock_token"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  add_index "users", ["email"], name: "index_users_on_email", unique: true, using: :btree
  add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", using: :btree
end