add example in readme.txt

readme.txt

@@ -8,3 +8,15 @@ My version Drupal Batch API for WordPress.
 
 == Description == 
 
+Example code:
+
+    $batch['title']='Title';
+    $batch['operations'][]=array('test_batch_operation',array());
+    
+    batch_operations_start($batch);
+    
+    function test_batch_operation(&$context) {
+      file_put_contents( ABSPATH . 'test.txt', "batch work" );
+      $context['message'] = 'Yeap! Work!';
+    }
+