[PATCH] Adding min_size and max_size to first_name, last_name and user_name

[Lucas]

Hello,

I made and attached a patch adding min_size and max_size options to Name's first_name and last_name and Internet's user_name.

I also added some test cases, which I believe cover the new functionality.

Please review my patch.

Lucas Uyezu

P.S Thanks for creating the gem, it's *very* useful.