Even so zeus is mainly used as a rails preloader it can be used for just about any environment which might benefit from preloading.
For an example on how to set this up checkout the custom_plan as well as the zeus.json file. In essance zeus forks on every step along the way down to the command, to minimize reload effort.
To run this example simple do the following
$ bundle install --binstubs
$ bin/zeus start
(in a different terminal)
$ zeus rake sth
To keep things simple zeus is installed in the binstubs in this example