[Wtr-general] [OT] - Gem upgrade?

[Raghu Venkataramana]

How does one upgrade gems? when I do a gem install on the latest gem, I 
find two versions of the same application installed:

for example,
wet-web (0.5, 0.9)

I am only left with an option to first uninstall the previous version of 
GEM and then installing the new one. Is there a way to specify (while 
installing the gem) that only the latest version needs to be kept and 
the previous version can be removed?

Any help is appreciated

Raghu