[icehawk219]

I had the same exact problem with a side project that spiraled out of control and was eventually cancelled in favor of a new job. What I had just started at the end, and what friends have done, that seems to work really well is to use something like Trello or Asana (which is a semi-ironic recommendation since my project would've been a competitor to these two) and lay out your immediate goal right now. Don't write any more code until you have that figured out. Then start entering tasks/ideas/features/bugs/etc that get you from wherever you currently are to that point.

I know someone who did this and has become disciplined about going back to that list whenever he starts working on the project to make sure the idea he's working on is on that list. If it isn't it's added to the "maybe one day" list on Trello and he switches gears over to some other task. Keeping in mind that tasks could be writing code but they could also be market validation as well. Of course he still has the issue of re-writing half of it every couple of weeks when he thinks the "old" code is now crap and needs to be refactored to perfection. That's a slightly more difficult hurdle to over come in my opinion.