support custom fields for timesheets, customers, projects and activities (#871)

src/Entity/CustomerMeta.php

@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Entity;
+
+use Doctrine\ORM\Mapping as ORM;
+use Symfony\Component\Validator\Constraints as Assert;
+
+/**
+ * @ORM\Entity()
+ * @ORM\Table(name="kimai2_customers_meta",
+ *      uniqueConstraints={
+ *          @ORM\UniqueConstraint(columns={"customer_id", "name"})
+ *      }
+ * )
+ */
+class CustomerMeta implements MetaTableTypeInterface
+{
+    use MetaTableTypeTrait;
+
+    /**
+     * @var Customer
+     *
+     * @ORM\ManyToOne(targetEntity="App\Entity\Customer", inversedBy="meta")
+     * @ORM\JoinColumn(onDelete="CASCADE")
+     * @Assert\NotNull()
+     */
+    private $customer;
+
+    public function setEntity(EntityWithMetaFields $entity): MetaTableTypeInterface
+    {
+        if (!($entity instanceof Customer)) {
+            throw new \InvalidArgumentException(
+                sprintf('Expected instanceof Customer, received "%s"', get_class($entity))
+            );
+        }
+        $this->customer = $entity;
+
+        return $this;
+    }
+
+    public function getEntity(): ?EntityWithMetaFields
+    {
+        return $this->customer;
+    }
+}