User register system, minor cosmetic changes, start of user authorisation

app/Policies/SystemPolicy.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace App\Policies;
+
+use Illuminate\Auth\Access\HandlesAuthorization;
+
+use App\Models\{System,User};
+
+class SystemPolicy
+{
+	use HandlesAuthorization;
+
+	/**
+	 * Determine whether the user can update the model.
+	 *
+	 * @param  \App\Models\User  $user
+	 * @param  \App\Models\System  $system
+	 * @return \Illuminate\Auth\Access\Response|bool
+	 */
+	public function update(User $user, System $system)
+	{
+		return (! $system->exists) || $system->users->contains($user) || $user->isAdmin();
+	}
+}