Acts as votable should be config variable, not source code edit

[factoidforrest]

Hey, great gem! I was thinking that you shouldn't ask users to edit your gem source for configuration, in case they want to update in which case the app will break. If elight is cool with this but doesn't have time, I would be happy to submit a pull request. Just want to make sure it will get accepted first.
PS: the docs say to change two lines and then only list one line.