Add distributional information (data, scores, coefs) to DB

Some reasons this might be valuable:

* Gelman's "secret weapon" for tracking trends in coefficients over time: http://andrewgelman.com/2005/03/07/the_secret_weap/
* Tracking distribution of features/target can held identify issues in feature engineering. E.g., if proportion of target tends towards zero over time: is this evidence that the model is being utilized to really strong effect? Is there an issue with how we are constructing the target variable?

Should probably rename database. It's called "modeling_results" right now. Maybe just call it "project_db" or something like that.