#19 - year periods (#25)

* #19 - year periods

* #19 - fix

database/migrations/2022_01_19_093320_create_year_periods_table.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class() extends Migration {
+    public function up(): void
+    {
+        Schema::create("year_periods", function (Blueprint $table): void {
+            $table->id();
+            $table->integer("year")->unique()->index();
+            $table->timestamps();
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists("year_periods");
+    }
+};