Created class User
Use User class to handle registration
Added a new column 'online'
Keep working on User class
Writing unit test for User class
Unit test for User class settled for now
Modified ensure unique id function - format is different. We want underscore to split prefix and number
Do not want  as a property. Updating unit test as well
Properly log out
Applied the User class to login and signup
Wrote Deck, Tag, Card, and wrote unit test for adding deck and cards
Change the id column of 'tags' table to 'tagid'
Use post instead of get
Replace the procedures with class function calls
Add a function to refresh the object's properties
Allow no limit for delete_from
Simplifying the code by using the modules
Adding more functionalities to each class
Updating the module tests
Applying the User module to each file