Fix: migrations down column name

Author: justutiz

src/Migrations/2015_10_10_000000_update_users_table

@@ -25,7 +25,7 @@ class UpdateUsersTable extends Migration
     public function down()
     {
         Schema::table('users', function (Blueprint $table) {
-            $table->dropColumn('role');
+            $table->dropColumn('role_id');
         });
     }
 }