diff --git a/lib/Migration/Version1000Date20200308073933.php b/lib/Migration/Version1000Date20200308073933.php
index 3fcab3dfe..ade94fd77 100644
--- a/lib/Migration/Version1000Date20200308073933.php
+++ b/lib/Migration/Version1000Date20200308073933.php
@@ -39,7 +39,7 @@ class Version1000Date20200308073933 extends SimpleMigrationStep {
 			'notnull' => true,
 			'default' => 0
 		]);
-		$table->addIndex(['participant'], 'deck_assigned_users_idx_t');
+		$table->addIndex(['type'], 'deck_assigned_users_idx_t');
 
 		return $schema;
 	}