Add trait for soft-deleted entities

[MAILPOET-2216]

lib/Doctrine/EntityTraits/DeletedAtTrait.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace MailPoet\Doctrine\EntityTraits;
+
+use DateTimeInterface;
+
+trait DeletedAtTrait {
+  /**
+   * @Column(type="datetimetz", nullable=true)
+   * @var DateTimeInterface|null
+   */
+  private $deleted_at;
+
+  /** @return DateTimeInterface|null */
+  function getDeletedAt() {
+    return $this->deleted_at;
+  }
+
+  /** @param DateTimeInterface|null $deleted_at */
+  function setDeletedAt($deleted_at) {
+    $this->deleted_at = $deleted_at;
+  }
+}