Merge pull request #2 from bzamansky/master

Making sure I have the latest before adding a visualization
Added d3 digraph visualization under the url /graph.

Files: digraph1.js digraph1.html and modified app.py

Notes: Nodes are only created for people who actually entered
crushlists - So, for example, if Abe had a crush on Sue and Tina but
Tina never entered a crush list, the only nodes in the graph would be Abe --> Sue.
Merge pull request #9 from zamansky/master

Added a d3.js visualastion (a digraph of crushes)