Rename Interfaces to Contracts to better match Laravel conventions

app/Contracts/Model.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace App\Contracts;
+
+/**
+ * Class Model
+ *
+ * @property mixed $id
+ * @property bool  $skip_mutator
+ */
+abstract class Model extends \Illuminate\Database\Eloquent\Model
+{
+    public const ID_MAX_LENGTH = 12;
+
+    /**
+     * For the factories, skip the mutators. Only apply to one instance
+     *
+     * @var bool
+     */
+    public $skip_mutator = false;
+}