First Commit of Project Biblioteca
Gestors interfaces implemented
Controllers added
Gestor Tests implemented
Models implemented
packages definition
LibroController Implemented
Libro Controller implemented
GestorLibro implemented
GestorLibroTest is running successfully
LibroController implemented GestorLibro Implemented
Singleton pattern added to Gestors classes. It´s necesary to use other
Gestors as a Services
PrestamoController and GestorPrestamo implemented.
Fixed some bugs
NOTE: In the 2 previous commits, when I said LibroController and
GestorLibro I mean UsuarioController and GestorUsuario

App is running properly
Tests have been passed successfully
Bug reparado