During a 24 hour hackathon, I made the basis of an app called Brain Marks. I just published it on the App Store!
The user can copy a tweet URL, add it to the app, categorize it. This allows you to categorize and save tweets! As opposed to the default bookmarks feature in Twitter.
If you want to see the whole story of how the app was created, you can look at this twitter thread
All the code can be viewed here! If you’d like to see it