Recently Studied Sets on VUS Dashboard

[IMGROOT2]

This feature should be added to the VUS Dashboard: #265

To minimize the writes to the database, information on recently studied sets will be collected as follows:

1. User opens a set.
2. Set ID and timestamp are recorded and read to Local Storage.
3. After a set amount of time has passed, the information will be written to the database. If there are more than 10 Set ID-and-Timestamp "pairs," the oldest recorded "pairs" will be deleted (In other words, only the ten latest opened sets that are opened will be in Firebase). This saves storage, as people usually will not look for the 20th latest set they opened.
4. When the VUS Dashboard: /#account -> Vocabustudy Dashboard #265 is opened, the data will be read and outputted from the most recent "pair" at the top to the oldest "pair" at the bottom in a news-article-feed sort of viewer. The latest 5 sets will be automatically shown. Then, if the user clicks "Load More", it will display the last 5 "pairs", provided there are 5 more "pairs" in the database (new users, for example, will only have 1 new set added when they click "Load More", if they only have opened 6 sets)

This is my vision, please let me know if you have any other ideas.