*/
 class Group {
        /**
-        * @var integer
+        * Primary key
         */
-       protected int $id;
+       protected ?int $id = null;
 
        /**
-        * @var \DateTime
+        * Create datetime
         */
        protected \DateTime $created;
 
        /**
-        * @var \DateTime
+        * Update datetime
         */
        protected \DateTime $updated;
 
        /**
-        * @var ArrayCollection
+        * Users collection
         */
        protected Collection $users;
 
                //Set defaults
                $this->created = new \DateTime('now');
                $this->updated = new \DateTime('now');
+
+               //Set collections
                $this->users = new ArrayCollection();
        }
 
         *
         * @return integer
         */
-       public function getId(): int {
+       public function getId(): ?int {
                return $this->id;
        }