Add migration for is_unique

Signed-off-by: snipe <snipe@snipe.net>

database/migrations/2022_02_16_152431_add_unique_constraint_to_custom_field.php

@@ -0,0 +1,32 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class AddUniqueConstraintToCustomField extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::table('custom_fields', function (Blueprint $table) {
+            $table->boolean('is_unique')->nullable()->default(0);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::table('custom_fields', function (Blueprint $table) {
+            $table->dropColumn('is_unique');
+        });
+    }
+}