Add historic airports to database

app/Console/Commands/PopulateAirportTimezones.php

@@ -17,7 +17,10 @@ class PopulateAirportTimezones extends Command
      */
     public function handle()
     {
-        Airport::whereNull('timezone')->chunkById(100, function ($airports) {
+        Airport::where(function ($query) {
+            $query->whereNull('timezone')
+                ->orWhere('timezone', 'Undefined');
+        })->chunkById(100, function ($airports) {
             foreach ($airports as $airport) {
                 $zoneName = null;
                 $attempts = 0;