Check the user DB model update() function

[vaasuu]

It should only change the things that are provided. It might be broken and set empty fields to null.

[vaasuu]

The code works as intended: it will set value to NULL in DB if the key matches but value is null, else it will update the value.

{first_name: "steve", last_name: undefined} -> will set first_name to steve and last_name to NULL in DB.