Added role_id UNSIGNED to the user migration, Validation to the data passed through the prompt and a Seeder for the DB

Right now the migrations throw an error when they are executed. The problem was that the CreateUserTableMigration was mission the role_id UNSIGNED column.

Also added validation that checks the data passed via the prompt.

Last, added a seed to the package, that way when the user installs the package and then execute the seed, gets some basic rows for the admin user in the roles, permissions and user table.