add planet vienna.rb feed list

Hello,

  As suggested at yesterday's meetup - in case there's any interest - here's a working first  Planet vienna.rb  feed list e.g. planet.ini. That's really all that's needed. 

 The Heroku hosted Sinatra web app will fetch the planet.ini from the vienna.rb repo (*) once a day (and update itself) plus fetch all feeds and update the planet site running for now @ http://viennarb.herokuapp.com

   There's a another stacked Sinatra app for the "backend" available @ http://viennarb.herokuapp.com/db

   Anyways, if there's any interest I invite you to update the planet.ini with more blogs from people, companies, projects, as you see fit.  Any questions, comments, ideas, etc. about Planet vienna.rb more than welcome. Cheers.

(*) Will add this feature with the next app update in the next days.