Allow the user to create custom short links rather than generating them using sha-256 hash based on the provided URL.
Constrains:
The custom string for the link have to be less than or equal to 8 characters
The custom string for the link have to be unique. If the same string exists in the database, don't create it and let the user know that string already exists in the database.
Custom short URL feature
Allow the user to create custom short links rather than generating them using
sha-256hash based on the provided URL. Constrains: