Rails app: users can post (/edit/update/delete) images (photos or gifs) with descriptions. Other functions include:
--users can tag each other in photos
--users can favorite photos (creates a list of their favorites that they can view; note can only favorite photos of other users)
--app generates a "recommendation engine": shows the user favorites of other users who have favorited at least one photo in common with the user (these recommendations do not include any photos the user has posted or favorited themselves)