Event statistics graphs

[drnikki]

Per our discussion in #9, It would be great if organizers had a way to make simple graphs that they could show in their closing speeches or wrap-up blogs. This could be as simple as a shared google sheets file that has some blanks filled in.

This reminds me, however, that in order to populate those graphs with data, organizers will also need to collect the data. Separate issue forthcoming on that.