I build my own gems as a way to distribute a variety of utilities where 
I work. What is the best way to install updates?

If I distribute a new gem file, provided by email/ftp/web how can a user 
install the update? Should they just re-install? "gem update <blah>" 
doesn't seem to have a "--local" option. If you place the file in your 
current directory, it seems to be ignored and I am not sure how to 
specify a gem update file. While "gem install" will automatically look 
both for the gem locally and remotely, "gem update" doesn't.

Maybe, this is a bad question since "gem update" is meant to look for 
updates that are not locally available. But this doesn't seem consistent 
with the way "gem install works".

How difficult is it to implement a simple gem server?