Validate if an username already exists in the database. If user does not exists, then it will return a true value, meaning that you can
use that as the userName. If the returned value is false, then the username is already taken, you will get a list of sugestions.
To run the tests in this program you can use this command:
>mvn test
To run the program you can use this commands:
>mvn clean install>mvn exec:java
Running the app you will find the following menu where you can choose what option you want:
Choose from these choices
1 - Verify if username is valid
2 - Add a restricted word
0 - Quit