Gem: ignoring dependencies doesn't work

[Michael Schuerig]

I'm trying to install a gem ignoring its dependencies. login_generator
requires rails, but that is already installed as a debian package.
Therefore I'm telling gem to force dependencies like this

gem install login_generator --force --remote --force --source
http://dist.leetsoft.com

Unfortunately, it doesn't work:

Attempting remote installation of 'login_generator'
Install required dependency rails? [Yn] n
ERROR: While executing gem ... (Gem:ependencyError)
Required dependency rails not installed

Now, is this a bug in gem or am I misunderstanding how forcing
dependencies is supposed to work?

Michael