Add some patterns to gitignore

src/Handler.php

@@ -61,6 +61,11 @@ class Handler {
     $content = array_merge_recursive($content, $options);
     $jsonFile = new JsonFile($projectRoot . '/composer.json');
     $jsonFile->write($content);
+
+    // Add some patterns to .gitignore.
+    foreach (['/vendor/', '/web/', '.env'] as $item) {
+      exec('git ignore ' . $item);
+    }
   }
 
   /**