Topic: Redesign App?

I don't really understand much about Rails or Ruby yet, especially ActiveRecord and I have weak design-fu. If this is the wrong place for this post please move it to the correct location. Sorry if this is a crappy explanation.

I have been working on building an app for a week or so now and have had lots of problems. This is my first rails app and I am needing to wrap it up, but keep getting stuck. My latest stick is with changing the type column, and I am thinking a redesign may be in order. Here is what I am working with.

I am building an app where a user on my site will sign up to be a respondent. The will enter their name, zip, email, and password. They will come back into the sight later and sign in using the email and password they provided. The only option this user will have is to finish filling out their profile. Once they finish they will be able to see upcoming events, surveys, and other opportunity's they may qualify for.

There are also admin users. An admin user will log in, be able to edit all respondents(previously mentioned users) and flag respondents with tags. They will also be able to create other admin users and update their own info. The part that throws all of this off for me is that they will also be able to create respondents, but these respondents that they create are not required to provide email addresses and are not always allowed to login (never if they don't have email).

I started out using sti on this and I'm starting to think that was wrong. Perhaps I should just do permission flags for each permission? When I was doing STI I had:

Potential Respondent

and the problem was validating when a potential respondent became a respondent.

Is there a better solution?

"They say, Evil prevails when good men do nothing. What they should have said was: Evil Prevails."