Great product and great to see that people are still working on things around RSS. One minor nitpick: You should have a search bar on the frontpage. Or rather the page you get when you click on the search button should be the frontpage, maybe with a bunch of links to the code, an about page, etc..
Out of curiosity, is there a business case as of now or is this a side-project mostly?
p.s. I love that you are using the latest Ruby and Rails
at the moment there is no business use case being a just started open source project, but there is an API and then companies can design what they want.
We need more search engines. Is there a way to see which rss feeds are in your index?