Feeds feature

Hi!

I was at lunch and now about to go out but added a series of commits for steps to make the simple feeds feature pass and also showcase some basic rails stuff. The commits are intended to be read in order and there's info in each commit message, I think it should be possible in a happy computer world to git checkout to each commit and run tests to see how things were at that point and what the next commit solves. 

Happy to discuss anything async via github comments ;)