first commit

app/Exceptions/Entities/AppAlreadyInstalledException.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace App\Exceptions\Entities;
+
+use Flugg\Responder\Exceptions\Http\HttpException;
+
+class AppAlreadyInstalledException extends HttpException
+{
+    protected $status = 400;
+
+    protected $errorCode = 'app.installation';
+
+    protected $message = 'App has been already installed';
+}