Refresh rails_account when account changed

This ensures `rails_account` will always match the assigned `account`,
making sure that features such as what rodauth-become_account provides
will work.

See adam12/rodauth-become_account#3.

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## HEAD
 
+* Refresh `rails_account` when `account` has changed (@janko)
+
 * Allow overriding `rodauth.rails_url_options` in the mailer (@janko)
 
 * Remove duplicate index on `account_id` in JWT refresh keys table (@janko)

lib/rodauth/rails/feature/base.rb

@@ -13,6 +13,7 @@ module Base
         end
 
         def rails_account
+          @rails_account = nil if account.nil? || @rails_account&.id != account_id
           @rails_account ||= instantiate_rails_account if account!
         end
 
@@ -59,7 +60,7 @@ def session
 
         def instantiate_rails_account
           if defined?(ActiveRecord::Base) && rails_account_model < ActiveRecord::Base
-            if account[account_id_column]
+            if account_id
               rails_account_model.instantiate(account.stringify_keys)
             else
               rails_account_model.new(account)

test/rodauth_test.rb

@@ -90,7 +90,7 @@ class RodauthTest < UnitTest
     assert_equal :login_required, error.reason
   end
 
-  test "returns current account if logged in" do
+  test "allows retrieving current account model instance" do
     assert_nil Rodauth::Rails.rodauth.rails_account
 
     account = Account.create!(email: "[email protected]", status: "verified")
@@ -99,6 +99,10 @@ class RodauthTest < UnitTest
     rodauth = RodauthApp.rodauth.allocate
     rodauth.instance_eval { @account = account_ds(account.id).first! }
     assert_equal account, rodauth.rails_account
+
+    account2 = Account.create!(email: "[email protected]", status: "verified")
+    rodauth.instance_eval { @account = account_ds(account2.id).first! }
+    assert_equal account2, rodauth.rails_account
   end
 
   test "allows using as a library" do