return [
    // ...
    'components' => [
        'authManager' => [
            'class' => 'yii\rbac\DbManager',
            // uncomment if you want to cache RBAC items hierarchy
            // 'cache' => 'cache',
        ],
        // ...
    ],
];

yii migrate --migrationPath=@yii/rbac/migrations

// ...
'user' => [
    'identityClass' => 'M91\UserModule\models\User',
    'enableAutoLogin' => true,
],
// ...

'modules' => [
    'user-module' => [
        'class' => 'M91\UserModule\Module',
    ]
]