code: protected function bootstrap(InputInterface $input, OutputInterface $output)
      {
          $this->setBootstrap($this->findBootstrapFile($input->getOption('bootstrap')));
  
          $container = $this->bootstrapContainer();
          $this->setContainer($container);
          $this->setAdapter($this->bootstrapAdapter($input));
  
          $this->setMigrations($this->bootstrapMigrations($input, $output));
  
          $container['phpmig.migrator'] = $this->bootstrapMigrator($output);
      }
docs: Bootstrap phpmig
  
  @return void