Change Airport tz field to timezone

app/Database/migrations/2017_06_11_135707_create_airports_table.php

@@ -14,7 +14,7 @@ class CreateAirportsTable extends Migration
             $table->string('name', 100);
             $table->string('location', 100)->nullable();
             $table->string('country', 64)->nullable();
-            $table->string('tz', 64)->nullable();
+            $table->string('timezone', 64)->nullable();
             $table->boolean('hub')->default(false);
             $table->unsignedDecimal('fuel_100ll_cost', 8)->nullable()->default(0);
             $table->unsignedDecimal('fuel_jeta_cost', 8)->nullable()->default(0);