Yo dawg, I heard you like Ruby...

postactivate

#!/bin/bash
# This hook is run after every virtualenv is activated.

export OLD_GEM_HOME=$GEM_HOME
export GEM_HOME=$VIRTUAL_ENV/gems/
export GEM_PATH=

export PATH=$VIRTUAL_ENV/gems/bin:$PATH

predeactivate

#!/bin/bash
# This hook is run before every virtualenv is deactivated.

export GEM_HOME=$OLD_GEM_HOME
unset GEM_PATH