Add groups, and the option for objects to be linked to one (or more) groups. #3128

app/Models/ObjectGroup.php

@@ -0,0 +1,21 @@
+<?php
+declare(strict_types=1);
+
+namespace FireflyIII\Models;
+
+
+use Illuminate\Database\Eloquent\Model;
+
+/**
+ * Class ObjectGroup
+ */
+class ObjectGroup extends Model
+{
+    /**
+     * @return \Illuminate\Database\Eloquent\Relations\MorphToMany
+     */
+    public function piggyBanks()
+    {
+        return $this->morphedByMany(PiggyBank::class, 'object_groupable');
+    }
+}