I mean, it kind of is. It's been abstracted certainly, and kanban was used for all kinds of project management before software but it was made by a software company that makes tools and products for programmers, who scratched their own itch first. Their initial customer base is developers because they're building on their existing Fog Bugz (and stackexchange a little bit, because of Joel), and you need to differentiate yourself more than you are.

Even based on the screenshots on your site, I'd look at that and say "I'm just going to use Trello".

I would just not bring Trello into the picture at all. Everyone who has knowledge of online management tools is going to compare you to them without your help. What you are doing is an online kanban tool for software development, with vim-like functionality in the browser.

Maybe something like "An opinionated kanban workflow for software projects". Make more out of the fact that you're doing less than your competition. You're exactly the right tool for a particular audience, play to that strength.