fix biest #736

db/migrations/5.1.27_add_index_to_cw_user_progresses_v50.php

+<?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);
+    }
+}