Nice project! I would advise to use $XDG_CONFIG_HOME instead of $HOME for storing the configuration file though :)
I hate XDG stuff so much. I just wish every app had their own folder in which they can put whatever they want. If home directory clutter is the issue, then just ~/crap/.{app1,..n} can be standardised. Basically, I want app/kinds-of-data and not the other way around.
Although I'll never forgive XDG for renaming etc to config and var to state. Would be so convenient to set PREFIX=~/.local for some things