Fixes issue with creating a talk.

Insert query had slides_link as field, but no value set for it.

Author: Mark Railton

src/models/TalkMapper.php

@@ -371,7 +371,7 @@ public function createTalk(array $data)
         $sql = '
           insert into talks (event_id, talk_title, talk_desc,
             slides_link, lang, date_given, duration)
-            values (:event_id, :talk_title, :talk_description,
+            values (:event_id, :talk_title, :talk_description, :slides_link, 
             (select ID from lang where lang_name = :language),
               :date, :duration)
          ';
@@ -384,6 +384,7 @@ public function createTalk(array $data)
             ':language'         => $data['language'],
             ':date'             => $data['date'],
             ':duration'         => $data['duration'],
+            ':slides_link'      => $data['slides_link'],
         ));
         $talk_id  = $this->_db->lastInsertId();