Improved permission regen performance by factor of 4

Worked around slower eloquent access to speed up permission generation.

app/Model.php

@@ -0,0 +1,19 @@
+<?php namespace BookStack;
+
+use Illuminate\Database\Eloquent\Model as EloquentModel;
+
+class Model extends EloquentModel
+{
+
+    /**
+     * Provides public access to get the raw attribute value from the model.
+     * Used in areas where no mutations are required but performance is critical.
+     * @param $key
+     * @return mixed
+     */
+    public function getRawAttribute($key)
+    {
+        return parent::getAttributeFromArray($key);
+    }
+
+}