Add a KnownUsers database with model

apps/accessibility/composer/composer/ClassLoader.php

apps/admin_audit/composer/composer/ClassLoader.php

apps/cloud_federation_api/composer/composer/ClassLoader.php

apps/comments/composer/composer/ClassLoader.php

apps/contactsinteraction/composer/composer/ClassLoader.php

apps/dav/composer/composer/ClassLoader.php

apps/encryption/composer/composer/ClassLoader.php

apps/federatedfilesharing/composer/composer/ClassLoader.php

apps/federation/composer/composer/ClassLoader.php

apps/files/composer/composer/ClassLoader.php

apps/files_sharing/composer/composer/ClassLoader.php

apps/files_trashbin/composer/composer/ClassLoader.php

apps/files_versions/composer/composer/ClassLoader.php

...lookup_server_connector/composer/composer/ClassLoader.php

apps/oauth2/composer/composer/ClassLoader.php

apps/provisioning_api/composer/composer/ClassLoader.php

apps/settings/composer/composer/ClassLoader.php

apps/sharebymail/composer/composer/ClassLoader.php

apps/systemtags/composer/composer/ClassLoader.php

apps/testing/composer/composer/ClassLoader.php