diff --git a/db/migrations/5.1.27_add_index_to_cw_user_progresses_v50.php b/db/migrations/5.1.27_add_index_to_cw_user_progresses_v50.php
new file mode 100644
index 0000000000000000000000000000000000000000..aaea146ee723042e9b9bf965286b9afee1942e73
--- /dev/null
+++ b/db/migrations/5.1.27_add_index_to_cw_user_progresses_v50.php
@@ -0,0 +1,22 @@
+<?php
+final class AddIndexToCwUserProgressesV50 extends Migration
+{
+    public function description()
+    {
+        return 'Alter cw_user_progresses table, add index for block_id';
+    }
+
+    public function up()
+    {
+        $query = "ALTER TABLE `cw_user_progresses`
+                  ADD INDEX `block_id` (`block_id`)";
+        DBManager::get()->exec($query);
+    }
+
+    public function down()
+    {
+        $query = "ALTER TABLE `cw_user_progresses`
+                  DROP INDEX `block_id`";
+        DBManager::get()->exec($query);
+    }
+}