Bugfix for the CK-Console

There was a bug on the CK Console where when you merged multiple image datasets the history of what image came from what dataset would be overwritten and only keep the record of the most recent merge. After looking through the code on the CK Console I found the cause of the bug and and created a pull request to resolve the issue.The bug currently prevents us from creating the art dataset and integrating it into our final deliverable. Hopefully this pull request should be approved soon.

https://github.com/cityknowledge/console/issues/15