Initial startup fix

[ryuslash]

Hi!

I'd stopped using Tekuti for a while and when I came back to it I noticed that I couldn't run the latest version of it anymore. I also noticed that a brand new setup had the same issue I did, which essentially comes down to the fact that there is no comment classification data for anything, and (as you can see through the second commit) there was an assumption that there would always be at least 1 commit in the git repository.

I honestly can't say I fully understand the code in classifier.scm, so if I'm going about this the entirely wrong way, please let me know, but these changes got both my collection of posts working again, and also made it possible for me to start up a new setup.