Rewrite rules and block installed if it's already installed

modules/Installer/Http/Controllers/InstallerController.php

@@ -31,6 +31,10 @@ class InstallerController extends AppBaseController
      */
     public function index()
     {
+        if(config('app.key') !== 'NOT_INSTALLED') {
+            return view('installer::errors/already-installed');
+        }
+
         return view('installer::index-start');
     }
 

modules/Installer/Resources/views/errors/already-installed.blade.php

@@ -0,0 +1,11 @@
+@extends('installer::app')
+
+@section('content')
+    <h2>phpVMS already installed!</h2>
+    <p>phpVMS has already been installed! Please remove the modules/Installer folder.</p>
+    {!! Form::open(['url' => '/', 'method' => 'get']) !!}
+    <p style="text-align: right">
+        {!! Form::submit('Go to your site >>', ['class' => 'btn btn-success']) !!}
+    </p>
+    {!! Form::close() !!}
+@endsection