public function moveCategories()
 {
     Component::where('class', 'Category')->get()->each(function (Component $c) {
         $entry = ['user_id' => $c->user_id, 'name' => $c->name];
         $category = Category::firstOrCreate($entry);
         Log::debug('Migrated category #' . $category->id . ': ' . $category->name);
         // create entry in category_transaction_journal
         $connections = DB::table('component_transaction_journal')->where('component_id', $c->id)->get();
         foreach ($connections as $connection) {
             DB::table('category_transaction_journal')->insert(['category_id' => $category->id, 'transaction_journal_id' => $connection->transaction_journal_id]);
         }
     });
 }