code: public function setup(\Pimple $app)
      {
          $config = $app['config'];
          \assert('$config instanceof \OctoLab\Common\Config\SimpleConfig');
          ConfigResolver::resolve($config['doctrine:dbal']);
          $app['connections'] = $app::share(function () use ($config) : \Pimple {
              $connections = new \Pimple();
              foreach ($config['doctrine:dbal:connections'] as $id => $params) {
                  assert('is_string($id)');
                  $connections[$id] = DriverManager::getConnection($params);
              }
              return $connections;
          });
          $app['connection'] = $app::share(function (\Pimple $app) use ($config) : \Doctrine\DBAL\Connection {
              $ids = $app['connections']->keys();
              $default = $config['doctrine:dbal:default_connection'] ?: current($ids);
              return $app['connections'][$default];
          });
      }
docs: @param \Pimple $app
  
  @throws \InvalidArgumentException
  
  @api