Added counters table for storing numbers of things statically.

database/2023_07_28_212101_create_counters_table.php

@@ -0,0 +1,16 @@
+<?php
+use Index\Data\IDbConnection;
+use Index\Data\Migration\IDbMigration;
+
+final class CreateCountersTable_20230728_212101 implements IDbMigration {
+    public function migrate(IDbConnection $conn): void {
+        $conn->execute('
+            CREATE TABLE msz_counters (
+                counter_name    VARBINARY(64) NOT NULL,
+                counter_value   BIGINT(20)    NOT NULL DEFAULT "0",
+                counter_updated TIMESTAMP     NOT NULL DEFAULT current_timestamp() ON UPDATE current_timestamp(),
+                PRIMARY KEY (counter_name)
+            ) ENGINE=InnoDB COLLATE=utf8mb4_bin
+        ');
+    }
+}