Check if synchronizations table exists

This prevents an error (table doesn't exist) that occurs when migrating for the first time.

Author: ramon-b

src/Listeners/MigrationStartedEventListener.php

@@ -2,6 +2,7 @@
 
 namespace LaravelSynchronize\Listeners;
 
+use Schema;
 use SplFileInfo;
 use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Config;
@@ -41,6 +42,10 @@ public function handle(MigrationStarted $migrationStarted)
             return;
         }
 
+        if (!Schema::hasTable(Config::get('synchronizer.table'))) {
+            return;
+        }
+
         $class = get_class($migrationStarted->migration) . 'Synchronization';
         $files = $this->synchronizer->getSynchronizations();