[25] Uniqueness of logins

[JaRutkowski]

Test scenario path:

• Login into the system as superuser (Administrator);
• Navigate into the 'Clients' tab;
• Register (add) new Client;
• Navigate into the 'Workers' tab;
• Register (add) new Worker with the same login as previously registered Client.

Test scenario description: The system should allow the user to create a Client role user with the same login as a Worker Librarian user or Worker Accountant user but not allows to create workers with the same logins (it means that we cannot create Worker Librarians with equals logins and f.eg. Worker Librarian and Worker Accountant with equals login).

[JaRutkowski]

TBD - consider using combo box on login form. It should be done to achieve the solution, but system should give the possibility to parametrise if that combo box can be displayed (that kind of solution cannot be implement now).