Remove commented code
Correctly displaying status of individual files and total progress bar
update file metadata in gridfs with dummy task_id for now
List the imagefiles in the tempalte when session is requested
Refactored celery app to share common code
Changing input to uploaders from a namespace to a dict
typo's and pep8
Using Process from billiard

* to allow daemonic processes creating more processes
Processing the file as celery task
Prepare to process an imagefile when upload concludes
Create celery app with flask app context attached to each task it runs
Move convenience methods to Session model
Refactor tasks for cyclic dependencies and nicer code
Remove pdb dependency
Overwrite files if already existing in image store
Doc: Descriptive workflow for user uploading the image
Updating metadata and cleanup after dicing is complete
Fetching file metadata while getting session listing
Fix attachments endpoint after moving _fetch_attachment
Showing status on upload on session page