I'm not sure what your experience is with web applications in general... but you should be okay without Ruby on Rails experience as long as you know the basic of web applications, apache, MySql, etc.. RoR is installed by default on all DreamHost servers, so that's taken care of.
There's a wiki page on using Ruby on Rails here:
I'm guessing that some installation instructions come along with the source code, but they may assume you already know how RoR works, etc.. I definitely get the feeling from the about page that the creator isn't focussed primarily on distribution, so you may have to figure a lot out for yourself. Also, make sure you check the license he's using... (from the download page: "The source code for TaskTHIS is made available strictly as a learning aid, under a modified LGPL license."). LGPL would be fine for you in general, but I don't know what the "modifications" are that he mentions on the download page.