Bug fixes for frontend/backend interaction with adding and retrieving…

[SabaHakimi]

With these changes:

• Tasks are automatically retrieved upon login (but not sorted by user yet)
• The weird half-size empty 'task' that used to appear when there are no tasks no longer appears
• Adding tasks works on both frontend and backend
• Functionality for removing tasks has been readded but is still buggy; causes an error or deletes multiple tasks sometimes.
  • I think this is due to indices being messed up with asynchronous updates from both adding and removing tasks.