Each library in SimplyE should be able to communicate to their patrons about features and occurrences within their library system without competing with other non-local libraries. As such, we would like to implement an alert/announcement system where an administrator for the library can add a simple text message to the circulation manager (where curation occurs) that will display to patrons when they next load that library catalog.

BRD: https://docs.google.com/document/d/1sp6lLdfssaDjsl-BiPi_N3H-ojdQln3qKesrd2AcIho/edit?usp=sharing

Data validation and implementation doc: https://docs.google.com/document/d/1ngvqr7oN-VHMdnygDD9uAeVpa45LYq-JUTT5zY5-gJ4/edit?usp=sharing

This feature is in-app only. This should require no UX since we're using the modal window.

Flow:

Every time the auth document is being fetch, for every announcement
1) Do nothing if announcement already presented
2) Else, present the content in modal view
3) Add the announcement id to the "presented list" after modal dismisses

Work needed:

1) Update auth document data model with Announcement
2) Present announcement with dismiss action
3) Store and access "Presented list" in UserDefault