Before you start the docker you must create folder folders2flickr. There you must copy uploader.ini from https://github.com/snoopy86/flickr-uploader. Go to http://www.flickr.com/services/apps/create/apply and apply for an API key Edit the following variables in the uploadr.ini.
Photos folder is where all your photos are stored.
When the docker is started you must check log. You will have to copy the url from log and put it in the browser to accept this app. You have 60s to do this :). After that uploader will get token from Flickr and start uploading your pictures to flickr.