Recently I was working on a project and wanted to be able to utilize Tidy to clean up some HTML output. I added the tidy_ffi gem to my project and voila, it worked! Or, to be more specific, it worked locally. Once I pushed to Heroku I started running into trouble, namely that libtidy.so, the dynamically linkable native library that tidy_ffi depends upon, wasn't found. Uh oh.