Beginnings of the RSVP system.

Here is how I imagine the flow:
  - There is an RSVP landing page for users to enter their "code"
  - They enter their code and are taking to a page with their details filled out (Name, guest names, number of allowed guests, etc.)
  - User enters RSVP information (simple Yes/No for single person, more complicated guest information for others)
  - RSVP information is recorded into DB and possibly emailed to Rob as a backup (since losing RSVPs = bad)

Other features that would be useful:
  - RSVP mail should allow them to go directly to the RSVP page without entering code (either through entering the URL manually, a short URL, or a QR code)
  - A "backup" RSVP system for users to enter all information in case they don't have/lost their code
  - Easy way for Rob/Natalie to record RSVPs for people that RSVP by other means
  - RSVP email to go out to invitee after RSVPing with thanks/regrets and an attached .ics file to add to their phones