add convenience setter

Author: Jamie Hannaford

src/Common/HydratorStrategyTrait.php

@@ -24,4 +24,12 @@ private function hydrate(array $data, array $aliases = [])
             }
         }
     }
+
+    private function set($key, $property, array $data, callable $fn = null)
+    {
+        if (isset($data[$key]) && property_exists($this, $property)) {
+            $value = $fn ? call_user_func($fn, $data[$key]) : $data[$key];
+            $this->$property = $value;
+        }
+    }
 }