Make slug optional

Author: antonkomarev

src/Blog/Entities/Blog.php

@@ -28,7 +28,7 @@ public function getWriters(): iterable;
 
     public function getId(): string;
 
-    public function getSlug(): string;
+    public function getSlug(): ?string;
 
     public function getName(): string;
 

src/Category/Entities/Category.php

@@ -21,7 +21,7 @@ public function getPosts(): iterable;
 
     public function getId(): string;
 
-    public function getSlug(): string;
+    public function getSlug(): ?string;
 
     public function getName(): string;
 

src/Post/Entities/Post.php

@@ -30,7 +30,7 @@ public function getComments(): iterable;
 
     public function getId(): string;
 
-    public function getSlug(): string;
+    public function getSlug(): ?string;
 
     public function getTitle(): string;