title: Geo Location in Ruby/Sinatra?
body: <p>I'm creating a small app in Sinatra, and I'd like to determine my users' cities from their zip code (which they would input), the distance between them and other users' (by zip code), and possibly a heat map of the zips.</p>
  
  <p>How would I do this?  I've tried the geoip gem, but it doesn't seem to do what I want.  Would I use an external service like Google Maps (obviously I'd need this for a heat map)?</p>
  
  <p>Thanks for any help.</p>