add migration for first info on zero knowledge

migrations/Version20210518212646.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20210518212646 extends AbstractMigration
+{
+    public function getDescription() : string
+    {
+        return '';
+    }
+
+    public function up(Schema $schema) : void
+    {
+        // this up() migration is auto-generated, please modify it to your needs
+        $this->addSql('ALTER TABLE poll ADD is_zero_knowledge TINYINT(1) DEFAULT NULL');
+    }
+
+    public function down(Schema $schema) : void
+    {
+        // this down() migration is auto-generated, please modify it to your needs
+        $this->addSql('ALTER TABLE poll DROP is_zero_knowledge');
+    }
+}