if (!await knex.schema.hasTable('auth_user_user_permissions')) {
    await knex.schema.createTable('auth_user_user_permissions', function(table) {
      table.increments().primary();
      table.integer('user_id').notNullable().references('auth_user.id');
      table.integer('permission_id').notNullable().references('auth_permission.id');