Continued with database work for permissions overhaul

Added to the entity_permissions table with further required fields and indexes.
Wrote the code for checking permissions.

app/Console/Commands/RegeneratePermissions.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace BookStack\Console\Commands;
+
+use BookStack\Services\RestrictionService;
+use Illuminate\Console\Command;
+
+class RegeneratePermissions extends Command
+{
+    /**
+     * The name and signature of the console command.
+     *
+     * @var string
+     */
+    protected $signature = 'permissions:regen';
+
+    /**
+     * The console command description.
+     *
+     * @var string
+     */
+    protected $description = 'Regenerate all system permissions';
+
+    /**
+     * The service to handle the permission system.
+     *
+     * @var RestrictionService
+     */
+    protected $restrictionService;
+
+    /**
+     * Create a new command instance.
+     *
+     * @param RestrictionService $restrictionService
+     */
+    public function __construct(RestrictionService $restrictionService)
+    {
+        $this->restrictionService = $restrictionService;
+        parent::__construct();
+    }
+
+    /**
+     * Execute the console command.
+     *
+     * @return mixed
+     */
+    public function handle()
+    {
+        $this->restrictionService->buildEntityPermissions();
+    }
+}