Allow referencing custom columns on new accounts

When using `ActiveRecord::Base.instantiate`, accessing a column
attribute that wasn't present in the given hash will raise a
ActiveModel::MissingAttributeError. This is not problematic for
retrieving existing accounts, as the `account` hash will have all the
columns, but it is for new accounts.

This allows things like running model validations in a
`before_create_account` hook instead of Rodauth validations, which is
especially useful when migrating existing authentication to Rodauth.

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## HEAD
 
+* Allow referencing custom column attributes on `rails_account` during account creation (@janko)
+
 * Drop support for Ruby 2.3 and 2.4 (@janko)
 
 ## 1.13.0 (2023-12-25) :christmas_tree:

lib/rodauth/rails/feature/base.rb

@@ -59,7 +59,11 @@ def session
 
         def instantiate_rails_account
           if defined?(ActiveRecord::Base) && rails_account_model < ActiveRecord::Base
-            rails_account_model.instantiate(account.stringify_keys)
+            if account[account_id_column]
+              rails_account_model.instantiate(account.stringify_keys)
+            else
+              rails_account_model.new(account)
+            end
           elsif defined?(Sequel::Model) && rails_account_model < Sequel::Model
             rails_account_model.load(account)
           else

test/integration/model_test.rb

@@ -0,0 +1,11 @@
+require "test_helper"
+
+class ModelTest < IntegrationTest
+  test "allows referencing custom columns for new accounts" do
+    visit "/create-account"
+    fill_in "Login", with: "[email protected]"
+    fill_in "Password", with: "supersecret"
+    fill_in "Confirm Password", with: "supersecret"
+    click_on "Create Account"
+  end
+end

test/rails_app/app/misc/rodauth_main.rb

@@ -37,6 +37,7 @@ class RodauthMain < Rodauth::Rails::Auth
     end
 
     after_login { remember_login }
+    before_create_account { rails_account.username }
 
     logout_redirect { rails_routes.root_path }
     verify_account_redirect { login_redirect }

test/rails_app/db/migrate/20200411171322_create_rodauth.rb

@@ -7,6 +7,7 @@ def change
       t.string :email, null: false
       t.index :email, unique: true, where: "status IN (1, 2)"
       t.string :password_hash
+      t.string :username
     end
 
     # Used if storing password hashes in a separate table (default)