Add hasSeed to the Lifetime entity (#1)

* Add hasSeed to the Lifetime entity

* Update Lifetime hadSeed to PHP7

Author: alexlongshaw

src/Entity/Lifetime.php

@@ -183,4 +183,15 @@ public function getSeed(string $name, int $numberOfValues, array $weights = null
 
         return $seed->getValue();
     }
+
+    public function hasSeed(string $name): bool
+    {
+        foreach ($this->seeds as $seed) {
+            if ($seed->getName() === $name) {
+                return true;
+            }
+        }
+
+        return false;
+    }
 }