Repeated users are saved in the database

[UO266618]

When making the insertion in the users database, they are saved repeated for the same solid id

[IsmaelAA]

Solved, by introducing some lines of code that check every time a user enters Mongo if there is more than one with the same id and deletes them if they do.
This is not the right way to do it, but it works.
17f2a41