fix ： chache save serialize bug

app/code/Joshine/InstagramFeed/Block/MediaFeed.php

@@ -153,7 +153,7 @@ class MediaFeed extends Template {
         }
         }
         $feed = $this->getMediaByApi();
         $feed = $this->getMediaByApi();
         if (isset($feed['data'])) {
         if (isset($feed['data'])) {
-            $this->cacheFeed($feed);
+            $this->cacheFeed($this->_json->serialize($feed));
         }
         }
         return $feed;
         return $feed;
     }
     }