You're letting the lack of requirements blind you. Depending on who you are, there's 2 ways to fix it: 1) Write some requirements! Clarify in your mind wher

You're letting the lack of requirements blind you. Depending on who you are, there's 2 ways to fix it: 1) Write some requirements! Clarify in your mind where the project is heading both in the short-term and the long-term. Agile-style user stories is one way to do both of those. 2) Start with the basics. Get the Rails framework set up. Get the DB set up. Start writing the schema. Etc. Once you've got the basics of every app (mvc, authentication, ACL, etc) then move on to what makes your app unique. Start with things that will provide benefit for you or your customers.