Dear maintainers,

While looking for the `gem` manpage, I found out there is no symlink
from /usr/share/man/man1/gem.1.gz to /usr/share/man/man1/gem3.1.1.gz, as
is done for the other cli commands installed by this package.

This is pretty inconvenient and it took me a good minute to understand I
needed to type `man gem3.1` to get the actual man page.

It seems this spawns from DEBIAN_RUBY_PROGRAMS in your d/rules file not
including the `gem` command. Adding it would create a new symlink and
solve the problem I was having.

Cheers,