model_tags is and abandoned project. I developed this for Radiant CMS 0.6.2 quite some time ago. The reason I don't work on this anymore is that the goal I had was reached. It worked and is working on websites I created, but I don't have the time to continuously update the code as Radiant evolves. If I will ever have new needs to be addressed by this plugin I will continue the work and update the code to the current Radiant version.