Added numeric check for slug attribut

application/symfony/src/Attribut/SlugAttribut.php

@@ -2,6 +2,8 @@
 
 namespace App\Attribut;
 
+use App\Exception\UnvalidValueException;
+
 /**
  * @author kevinfrantz
  */
@@ -12,16 +14,30 @@ trait SlugAttribut
      */
     protected $slug;
 
+    /**
+     * @param string $slug
+     *
+     * @throws UnvalidValueException
+     */
     public function setSlug(string $slug): void
     {
+        if (is_numeric($slug)) {
+            throw new UnvalidValueException('A slug must not be numeric!');
+        }
         $this->slug = $slug;
     }
 
+    /**
+     * @return string
+     */
     public function getSlug(): string
     {
         return $this->slug;
     }
 
+    /**
+     * @return bool
+     */
     public function hasSlug(): bool
     {
         return isset($this->slug);