title: monolog.logger.db service has been removed
body: <p>I'm trying to refactor some Symfony 3 code to Symfony 4. </p>
  
  <p>I am getting the following error when attempting to log:</p>
  
  <blockquote>
    <p>The "monolog.logger.db" service or alias has been removed or inlined
    when the container was compiled. You should either make it public, or
    stop using the conta     iner directly and use dependency injection
    instead.</p>
  </blockquote>
  
  <p>My logging code:</p>
  
  <pre><code>$logger = $container-&gt;get('monolog.logger.db');
          $logger-&gt;info('Import command triggered');
  </code></pre>
  
  <p>Monolog config:</p>
  
  <pre><code>monolog:
      channels: ['db']
      handlers:
          db:
              channels: ['db']
              type: service
              id: app.monolog.db_handler
  </code></pre>
  
  <p>app.monolog.db_handler config (Note, I tried <code>public: true</code> here and it had no affect:</p>
  
  <pre><code>app.monolog.db_handler:
      class: App\Util\MonologDBHandler
      arguments: ['@doctrine.orm.entity_manager']
  </code></pre>
  
  <p>How can I get this wired up correctly in Symfony 4?</p>