updated seeds.rb for _id refactor updates

It was a pleasure meeting you today! You were so nice, I figured I'd look at your issues on my bus ride home :)

I think I figured it out. You just missed a place you needed to change requester and receiver to requester_id and receiver_id. Using an IDE like rubymine might help you with refactors like this in the future.

I was able to successfully db:setup with this change and get the app up locally.

Keep going!