Add checkbox to clear previous data when importing #490 (#546)

* Add checkbox to clear previous data when importing #490

app/Models/Enums/ImportExportType.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace App\Models\Enums;
+
+use App\Contracts\Enum;
+
+class ImportExportType extends Enum
+{
+    public const AIRLINE = 1;
+    public const AIRCRAFT = 2;
+    public const AIRPORT = 3;
+    public const EXPENSES = 4;
+    public const FARES = 5;
+    public const FLIGHTS = 6;
+    public const SUBFLEETS = 7;
+
+    public static $labels = [
+        self::AIRLINE   => 'airline',
+        self::AIRCRAFT  => 'aircraft',
+        self::AIRPORT   => 'airport',
+        self::EXPENSES  => 'expense',
+        self::FARES     => 'fare',
+        self::FLIGHTS   => 'flight',
+        self::SUBFLEETS => 'subfleet',
+    ];
+}