Filter the upcoming subject queue for duplicates (#3770)
Filter the upcoming subject queue for duplicates (#3770)

* Filter the upcoming subject queue for duplicates

* Add a comment explaining the array filter

amyrebecca/Panoptes-Front-End,jelliotartz/Panoptes-Front-End,amyrebecca/Panoptes-Front-End,zooniverse/Panoptes-Front-End,jelliotartz/Panoptes-Front-End,jelliotartz/Panoptes-Front-End,amyrebecca/Panoptes-Front-End