A method includes storing a plurality of content items and storing one or more associations. Each of the associations includes an association between exactly two of the content items. The method may also include causing a graphical user interface (GUI) to be presented on an electronic device. The GUI may include a first representation of a first content item, a list of representations comprising a second representation of a second content item and a third representation of a third content item, a first visual indicator indicating a first association between the first content item and the second content item, and a second visual indicator indicating a second association between the first content item and the third content item. The method may also include receiving a user input comprising an instruction to create an additional association between the first content item and the second content item.